HomeMy WebLinkAboutStaff Report 5.A 01/28/2019 Attachment 24Responses to Comments
on the
Initial Study/Mitigated
Negative Declaration (IS/MND)
for the
Safeway Fuel Center
Petaluma, California
December 3, 2018
Phyllis Fox, PhD, PE
and
Ray Kapahi, BSC, M Eng
ATTACHMENT 24
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TABLE OF CONTENTS
1. INTRODUCTION AND SUMMARY...........................................................................................1
2. SCIENTIFIC RESEARCH CONFIRMS HEALTH IMPACTS ARE SIGNIFICANT ............... 2
3. CRITIQUE OF REVISED SAFEWAY HEALTH RISK ASSESSMENT.....................................3
3.1. Validity of Meteorological Data............................................................................................. 3
3.2. Emission Factors...................................................................................................................... 3
3.3. Exposure Duration...................................................................................................................4
4. CRITIQUE OF BAAQMD COMMENT LETTER DATED NOVEMBER 8, 2018 .................... 5
4.1. Reliance on Santa Rosa Meteorological Data....................................................................... 5
4.2. Benzene Emission Factor........................................................................................................ 5
4.3. Residential Exposure Assumptions...................................................................................... 6
5. RECENT RESEARCH DEMONSTRATES CANCER HEALTH RISKS OF THE.
PROJECT ARE SIGNIFICANT.............................................................................................. 7
5.1. Safeway Significantly Underestimated Benzene Emissions .............................................. 7
5.2. Setback Distances...................................................................................:...............................12
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1. INTRODUCTION AND SUMMARY
Safeway proposes to develop a fuel station at 335 South McDowell Boulevard in
Petaluma (Project) in the Washington Square Shopping Center. The fuel station will have 16
fuel positions (8 pumps with 2 fuel positions per pump) to accommodate the simultaneous
fueling of SUVS, full-size pickup trucks, and passenger vehicles. The annual throughput of
gasoline is asserted not to exceed 8.5 million gallons. The fuel dispensers will be served by two
20,000 -gallon underground storage tanks that will be serviced by twice-daily truck deliveries of
fuel, lasting 30 to 40 minutes. The Project also includes a 697 -square foot convenience store,
vehicle parking adjacent to the convenience store, landscaping, and an exit driveway.'
We submitted comments on the Initial Study/Mitigated Negative Declaration
(IS/MND) on September 17, 2018.2 The Applicant3 and the BAAQMD4 have provided
responses to some of those comments. Based on our review and analysis of new information
presented in these responses, we have revised our health risk assessment (HRA), which has
been separately submitted. Our revised HRA continues to demonstrate that the Project will
result in significant cancer risks at nearby sensitive receptors, including at residences along
South McDowell Boulevard, at the North Bay Children's Center (60 feet away), and in the
recreational playfield.
Our results are consistent with numerous scientific studies published in refereed
journals that have linked residential proximity to gas stations and increased risk of adverse
health outcomes, including increased risk for cancer, and specifically for leukemia in children.
As we demonstrate below, there's no reason to quibble over the details of complex HRAs
because numerous scientific studies, published in highly regarded scientific journals, have
demonstrated that proximity to gas stations results in significant increases in cancer in
surrounding populations.
A Negative Declaration can be prepared only when there is no substantial evidence in
light of the whole record before the lead agency that the project may have a significant effect on
the environment.5 We have presented substantial unrefuted evidence that the proposed
Safeway gas station will result in significant cancer risks in the surrounding community. An
City of Petaluma, Safeway Fuel Center Initial Study/Mitigated Negative Declaration (IS/MND), 335
South McDowell Boulevard, March 29, 2018, pp. 5-6; available at http://cityofpetaluma.net/cdd/maior-
proj_ects.html,
2 Phyllis Fox and Ray Kapahi, Comments on the Initial Study/Mitigated Negative Declaration (IS/MND)
for the Safeway Fuel Center, September 17, 2018 (9/17/18 Fox/Kapahi Comments).
3 Letter from Matthew D. Francois, Rutan & Tucker, LLP, to Heather Hines, City of Petaluma, Re:
Safeway Fuel Center Project—Responses to Comments of Bay Area Air Quality Management District and
Phyllis Fox/Ray Kapahi, October 10, 2018 (10/10/18 Rutan Letter).
4 Letter from Damian Breen, BAAQMD, to Olivia Ervin, City of Petaluma, Re: Safeway Fuel Center
Project—Air District Comments on Health Risks Assessments, November 8, 2018 (11/8/18 BAAQMD
Letter).
5 PRC § 21080(c)),14 C.C.R. § 15070).
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environmental impact report (EIR) must be prepared when there is substantial evidence in the
record that supports a fair argument that significant effects may occur.6 Our analysis below
indicates that there is substantial evidence that the Project will result in significant cancer
impacts, requiring that an EIR be prepared.
2. SCIENTIFIC RESEARCH CONFIRMS HEALTH IMPACTS ARE SIGNIFICANT
The health risk assessments (HRAs) prepared by the various parties — the Bay Area Air
Quality Management District (BAAQMD), Safeway's consultants (Illingworth & Rodkin), and
the affected community (Fox/Kapahi) are highly complex analyses prepared by parties with
various interests in their outcomes. However, scientific research, conducted by parties with no
interests in this case, have linked residential and school proximity to gas stations to an increased
risk of adverse health outcomes7—including increased risk for cancer$ and, specifically,
leukemia in children.9 We previously submitted the supporting scientific papers into the record
and will not resubmit them here.
Living next to a gas station quadruples the risk of acute leukemia in children and
increases the risk of developing acute non -lymphoblastic childhood leukemia by 7 times,
compared with children who do not live near a gas station.10 Moreover, a significant exposure -
response relationship exists between the likelihood of childhood leukemia and the number of
gasoline stations per square mile.11 Thus, gas stations should not be located in areas where
housing or vulnerable populations and activities exist or are proposed, including settings such
as those near the Project, with residences across the street and schools within 300 feet.
A study by Johns Hopkins School of Public Health reports that even small spills at gas
stations— "droplets of fuel"—cumulatively cause long-term environmental damage to soil and
groundwater in residential areas close to the stations, resulting in significant public health
6 PRC § 21080(d
7 J. D. Brender et al., "Residential Proximity to Environmental Hazards and Adverse Health Outcomes,"
American Journal of Public Health 101, no. S1 (2011): S37 -S52.
8 E. O. Talbot, "Risk of Leukemia as a Result of Community Exposure to Gasoline Vapors: A Follow -Up
Study," Environmental Research 111, no. 4 (2011): 597-602.
9 P. Brosselin et al., "Acute Childhood Leukaenua and Residence Next to Petrol Stations and Automotive
Repair Garages: The ESCALE Study (SFCE)," Occupational and Euvironntental Medicine 66, no. 9 (2009):
598-606; P. F. Infante, "Residential Proximity to Gasoline Stations and Risk of Childhood Leukemia,"
American Journal of Epidemiology 185, no. 1 (2017): 1-4; C. Steffen et al., "Acute Childhood Leukemia and
Environmental Exposure to Potential Sources of Benzene and Other Hydrocarbons: A Case -Control
Study," Occupatimal and Environmental Medicine 61, no. 9 (2004): 773-778; C. Steinmaus and M. Smith,
"Parental, In Utero, and Early -Life Exposure to Benzene and the Risk of Childhood Leukemia: A Meta -
Analysis," American Jountal of Epidemiology 183, no. 1 (2016):1-14.
to Brosselin et al., 2009; Steffen et al., 2004.
11 H. H. Weng et al., "Childhood Leukemia and Traffic Air Pollution in Taiwan: Petrol Station Density as
an Indicator," Journal of Toxicology and Envirottntental Health A 72, no. 2 (2009): 83-87.
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risks.12 Large filling stations can dispense as much as 1 million gallons fuel/month (12 million
gallons/year).
3. CRITIQUE OF REVISED SAFEWAY HEALTH RISK ASSESSMENT
3.1. Validity of Meteorological Data
The revised HRA asserts that "The WRF model pulls in observations and archived
meteorological data from the region around the Project site.... "13 This is incorrect. The WRF
meteorological data used by the Applicant's consultant was not based on observations recorded
at or near the project site in Petaluma. Lakes Environmental, which prepared the WRF
meteorological data used by the Applicant's consultant, confirmed to Mr. Kapahi that the WRF
model is not set up to utilize direct input of any local meteorological data. See Exhibit 1, which
is the email exchange with Lakes Environmental. The WRF model used in Safeway's analysis
has a resolution that is regional and not site or source specific. Accordingly, it is not intended to
be used, nor is it appropriate to be used, for a site-specific health risk assessment at this fine
scale. The minimum resolution available with WRF model as used in the most recent HRA by I
& R is in the range of 1 to 4.kilometers. Given this resolution, it is not possible to make accurate
predictions within 50 to 100 meters.
3.2. Emission Factors
Diesel particulate emissions (DPM) are a major contributor to public health risks. Thus,
it is critical that accurate emission factors for determining the emission rates of DPM be used.
The emission factor for heavy-duty diesel delivery trucks used in Safeway's analysis is 0.03221
grams of PM2.5 per mile, based on a vehicle speed of 5 mph. The emission factor based on the
EMFAC model for Sonoma County for calendar year 2019 is 0.063 grams/mile, or double what
was used in the Applicant's calculation. A similar discrepancy appears for light-duty vehicles
(LDA):
Vehicle Category
Used in the Safeway HRA
(gram/mile) [pdf Page 29]
Listed in EMFAC Model
(gram/mile)
LDA
0.024008
0.087806
Understating the emission rates of DPM by a factor of 4 directly leads to
underestimating public health risks. We used EMFAC to estimate emissions of DPM,
12 M. Hilpert and P.N. Breysse, "Infiltration and Evaporation of Small Hydrocarbon Spills at Gas
Stations," Jotiriial of C011ta711i71a11t Hydrology, v.170,(2014):39-52.
1310/10/18 Rutan Letter, 10/10/18 I&R Memo, pdf 13.
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recommended by the BAAQMD's CEQA Guidelines.14 The following tables present the actual
EMFAC results used in our analysis for heavy -heavy duty and light-duty vehicles.
EMFAC2014 (0.0.7) Emission Rates
Region Type: County
Region: Sonoma
Calendar Year. 2019
Region Type: County
Vehicle Classification: EMFAC2007Categories
Units: miles/day for VMT, g/mile for RUNEX, PMBW and PMTW
Region !CalYr VehClass MdlYr (Speed
Fuel
Sonoma 2019 LDA Aggregate
Region: Sonoma
Sonoma 2019 LDA Aggregate
10 DSL
Sonoma 2019 LDA Aggregate
15,DSL
Sonoma 2019 LDA Aggregate
20 DSL
Calendar Year: 2019
Season: Annual
Vehicle Classification: EMFAC2007Categories
Units: miles/day for VMT, g/mile for RUNEX, PMBW and PMTW
Region iCalYr VehClass;MdlYr Speed
Fuel
VMT
ROG_RUNTOG_RUNCO_RUNE:NOx_RUNCO2_RUNIPMIO_RUIPM2_5_RUNEX
Sonoma 2019 HHDT Aggregate
5 DSL
1269.665
0.907418 3.252055,
8.000291'
20.47671!
4589.594 0.066444
0.06357,
Sonoma 2019 HHDT AggregatE
10 DSL
3926.696
0.76558 2.23991
5.7704831
16.61248
3821.149 0.062739
0.060025'
Sonoma 2019'HHDT Aggregate
15 DSL
3971.48
0.550222 1.028745'
3.089707,
11.40913
2743.792. 0.053964
0.051629',
Sonoma 2019 HHDT AggregatE
20, DSL
23007.28
0.363347 0.45624
1.60128
7.73209
2124.615 0.053474,`0.051161
EMFAC2014 (v1.0.7) Emission Rates
Region Type: County
Region: Sonoma
Calendar Year. 2019
Season: Annual
Vehicle Classification: EMFAC2007Categories
Units: miles/day for VMT, g/mile for RUNEX, PMBW and PMTW
Region !CalYr VehClass MdlYr (Speed
Fuel
Sonoma 2019 LDA Aggregate
5',DSL
Sonoma 2019 LDA Aggregate
10 DSL
Sonoma 2019 LDA Aggregate
15,DSL
Sonoma 2019 LDA Aggregate
20 DSL
3.3. Exposure Duration
VMT ROG_RUNTOG_RUN'CO_RUNENOx_RUNCO2_RUNIPMIO_RUIPM2 5 RUNEX
18.65869 0.284867 0.324302 3.569349 0.28606 721.2901 0.091776 0,087846'
214.4412 0.2078051 0.236572 2.663858 0.28083 604.4364 0.065939 0.063087
930.7187 0.122855 0.139862 1.437057 0.28592 507.2989 0,04987 0.047712
3035.568 0.071016 0.080847 0.693976 0.277533 417.1567 0.038615 0.036944'
There are various guidelines for an appropriate exposure duration for use in an HRA,
ranging from 30 years to 70 years. The Office of Environmental Health Hazard Assessment
(OEHHA) recommends a 30 -year exposure duration. This exposure duration is referenced by
the Applicant and in BAAQMD's Comment letter dated November 8, 2018. However, the
BAAQMD's own Guidance15 on preparing risk assessments for gas stations requires the use of a
70 -year exposure. See Exhibit 4, BAAQMD Air Toxics NSR Program Health Risk Assessment
Guidelines (December 2016). These Guidelines were never revised, and therefore remain
current. These Guidelines provide in relevant part:
14 BAAQMD, California Environmental Quality Act, Air Quality Guidelines, May 2017, pdf 61; available
at:httt)://wwr.baaomd.gov/-/media/files/Planninz-and-research/ceaa/ceaa guidelines mav2017-
pdf.pdf?la=en.
15 BAAQMD Health Risk Assessment Guidelines, December 2016; available at:
http: / / www.baagind.gov/ - / media/files /planning -and -research/ permit-
modeling/hra guidelines 12 7 2016 clean-pdf.pdf.
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2.2.1.3 Exposure Duration
Based on OEHHA's 2003 HRA Guidelines, the Air District will estimate
cancer risk to residential receptors for gasoline dispensing facilities based on a
70 -year lifetime exposure. Although 9 -year and 30 -year exposure scenarios may
be presented for information purposes, risk management decisions will be made
based on 70 -year exposure duration for residential receptors. For worker
receptors for gasoline dispensing facilities, risk management decisions will be
made based on OEHHA's 2003 recommended exposure duration of 40 years.
Cancer risk estimates for children at school sites will be calculated based on a 9 -
year exposure duration.
These Guidelines specifically state that the District's HRA Guidelines "...generally
conform to the Health Risk Assessment Guidelines adopted by Cal/EPA's Office of
Environmental Health Hazard Assessment (OEHHA) for use in the Air Toxics Hot Spots
Program for all types of facilities except gasoline dispensing facilities (GDFs)."16 Contrary to this
guidance, the Applicant used 30 years. When the District provides guidance for a particular
industry, that guidance needs to be followed rather than other general guidance. Safeway's use
of a 30 -year exposure duration understates the public risk. The 70 -year exposure used in our
analysis is more appropriate and is consistent with relevant guidance.
4. CRITIQUE OF BAAQMD COMMENT LETTER DATED NOVEMBER 8, 2018
The BAAQMD's comment letter dated November 8, 2018 ("BAAQMD Letter") is less
than a single page in length and does not represent a serious effort by a regulatory agency
charged with protecting human health from air emissions. The comments raised in the
BAAQMD letter lack specificity, much less adequate reference to current regulatory guidance or
practices. Each comment from the BAAQMD Letter is addressed and dismissed below.
4.1. Reliance on Santa Rosa Meteorological Data
The BAAQMD letter criticizes our earlier reliance on Santa Rosa meteorological data but
offers no specific explanation as to why our methodology was inappropriate. Our prior
comment letter explained why it was necessary to rely on Santa Rosa data, and further
explained that the respective wind patterns for Santa Rosa and Petaluma mean that the actual
health impacts would be more significant than we previously modeled. Nevertheless, we were
able to obtain AERMOD-consistent Petaluma meteorological data as described more fully
above. Consistent with our earlier prediction, use of Petaluma data reveals that the health risk
impact is significantly higher than previously modeled. Thus, this criticism has no merit.
4.2. Benzene Emission Factor
The BAAQMD letter criticizes our benzene emission factor as "substantially higher than
the Air District's standard benzene emission factor for gasoline dispensing facilities." Notably,
the BAAQMD Letter does not assert that our emission factor is incorrect or inappropriate, much
16 BAAQMD September 2016 Guidelines, p. 1.
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less cite any authority supporting this criticism. Contrary to this vague criticism, our benzene
emission factor is consistent with CAPCOA guidance. To the extent the BAAQMD currently
relies on a lower emission factor, that is a failure on the part of BAAQMD and not a deficiency
in our analysis. See Table 1. As documented in Tables 1 and 2, recent research shows that
actual benzene emissions from gas stations have been underestimated by CARB/CAPCOA and
therefore would be substantially greater than those estimated in our analysis.
4.3. Residential Exposure Assumptions
The BAAQMD letter states that our "residential exposure assumptions" are "not
consistent with the Air District's current HRA risk calculation procedures" (emphasis added).
Again, the BAAQMD letter is not specific as to which exposure assumptions are being
addressed, what the "proper" assumption is, or any supporting reference. To the extent that the
BAAQMD letter is criticizing our 70 -year residential exposure duration, that duration is
expressly required in the "BAAQMD Air Toxic NSR Program Health Risk Assessment
Guidelines." The Introduction to these Guidelines clearly states that OEHHA guidelines are
followed "for all types of facilities except gasoline dispensing stations (GDFs)."17 Section
2.2.1.3 of that guidance further states, "Based on OEHHA's 2003 HRA Guidelines, the Air
District will estimate cancer risk to residential receptors for gasoline dispensing facility based
on a 70 -year lifetime exposure."18 Similarly, Section 2.2.1.2 requires exposure assumptions of
"24 hours per day for 350 days per year." To the extent that BAAQMD's "current ...
procedures" are now deviating from its own published guidance, that represents a failure on
the part of BAAQMD to protect Bay Area residents and not a valid criticism of our analysis.
Finally, it should be clarified that the BAAQMD's November 8 letter does not address
the proposed gasoline stations DPM emissions, which are not regulated by BAAQMD. Further,
the BAAQMD's review failed to include other carcinogens known to be present in gasoline
vapors. The failure of the BAAQMD's November 8 letter to acknowledge these omissions,
which we identified in our initial comments, is inexcusable given that DPM emissions represent
a major source of human health risk from the Project.
In summary, emissions of carcinogens from the Safeway gasoline station would be much
greater than those presented in the latest submittal by the Applicant. If these deficiencies are
corrected, the Applicant's current risk analysis would yield cancer risks significantly greater
than the cancer significance threshold of 10 per million.
17 BAAQMD, December 2016, p. 2 (emphasis added).
18 BAAQMD, December 2016, p. 8.
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5. RECENT RESEARCH DEMONSTRATES CANCER HEALTH RISKS
OF THE PROJECT ARE SIGNIFICANT
5.1. Safeway Significantly Underestimated Benzene Emissions
Gasoline vapors from unburned fuel are released into the atmosphere at fuel stations
from five sources: (1) storage tank loading; (2) storage tank breathing (due to changes in
temperature); (3) vehicle refueling; (4) spillage; and (5) hose permeation. The loading,
breathing, and refueling emissions are released through the vent pipe, shown in Figure 1, and
are generally called "vent" emissions. Vent emissions are the major source of unburned fuel
(gasoline, diesel) and benzene, accounting for 66% to 70%19 of the total fuel vapors20 and hence
benzene. The balance of the benzene comes from spillage and hose permeation, both of which
are emitted directly into the air.
Figure 1. Schematic of Typical Gas Station
ATF%
rrniss{:.r�s 3
The responses argue that we "overstate the amount of benzene emissions, citing higher
emission factors from another air district, and then modeling even higher emissions than the
cited values."21 They further assert that their benzene emission factors are correct as they were
"based on the latest California Air Resources Board ("CARB") guidance... and were the same
factors used by BAAQMD to compute effects for the facility's permit... "22These assertions are
unsupported and incorrect. The CARB guidance is known to underestimate VOC and benzene
emissions from gas stations, as demonstrated below. The following discussion is based on
19 CARB, Revised Emission Factors for Phase 1 Gasoline Bulk Transfer at California Gasoline Dispensing
Facilities, December 23, 2013, Table I-1; available at: https://win=w.arb.ca.gov/vapor/gdf-
emisfactor/attachment 2%20-%2020%20nov%202013.pdf.
20 Based on refueling of Phase II non-ORVR vehicles.
2110/10/18 Francois Letter, p. 2.
22 10/10/17 I&R Memo, p. 3.
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VOCs because all parties assumed the same benzene content in fuel vapors, 0.003 pounds per
pound of VOC (lb/1b VOC).
Table 1 summarizes various estimates of VOC emissions from gasoline station sources.
This table shows that the total VOC emission factor used by BAAQMD and Safeway, 0.67
lb/1000 gal, is at the lower end of the range of reported VOC emission factors.
Table 1. VOC Emission Factors for Gasoline Fueling Stations (lb VOC/1000 gal)23
Source
SCA,, rvlD
Kapahi/
Fax
BA4QN1D
Safeway
CARB
fon-
ORVR
GARB
ORVR
'Wank Filling
8.15
0.08
0.15
0.15,
Vehicle Fueling
0.32
8.42
0.45
0.45
0.42
4.021
Breathing Lasses
4.424
0.03
4.424
4.424
Spillage
0.24
0.42
0.22
01.22
0.24
0.24
Hose Permeation
OM -4
0
4. 9
0.009
TOTAL
0.743
0.95
0.67
0.67
0.8433
0.444
The Applicant and BAAQMD also underestimated benzene emissions by omitting
emission sources. Their HRAs are based only on "refueling" and spillage emissions. These
analyses do not explain what is included in "refueling." However, the VOC emission factor
that was used, 0.45 pounds per thousand gallons of gasoline (lb/1000 gal),24 is too low to
plausibly include tank filling (see Table 2) and appears to be based only on refueling of Phase II
vehicles equipped with Onboard Refueling Vapor Recovery (ORVR) systems, assuming 100% of
visiting vehicles are so equipped. However, based on GARB estimates25 for 2018,15% of the
vehicles will not be equipped with ORVR. See Table 2. The Safeway and BAAQMD HRAs also
omitted hose permeation emissions.26 See Table 1. An underestimate in VOC emissions means
an underestimate in benzene because benzene emissions are calculated by multiplying the VOC
emissions by the benzene content in the fuel vapors. In sum, we know VOC and benzene
emissions are grossly underestimated by BAAQMD and Safeway for three reasons.
23 SCAQMD = SCAQMD, Proposed Amended Rule 1401—New Source Review of Toxic Air
Contaminants, August 2017, Table 2; BAAQMD & Safeway =10/10 Rutan Letter, BAAQMD Evaluation
Report, pdf 33; CARB ORVR & CARB Non-ORVR = CARB 2013.
24 10/10/18 Rutan Letter, Exhibit A, BAAQMD Evaluation Report, pdf 32.
25 CARB, Revised Emission Factors for Phase H Vehicle Fueling at California Gasoline Dispensing
Facilities, December 23, 2013, Table 1-2.
2610/10/18 Rutan Letter, Exhibit A, BAAQMD Evaluation Report, pdf 32.
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Table 2: CARB 2013 Revised and SCAQMD Proposed Controlled Gasoline Dispensing
Emission Factors (lbs VOC/1,000 gal)27
*SCAQ1D staff is committed to continue working ttrith CARR staff on the refueling emission factor for Phase II
EVR with OR%'R vehicles. Until then; SCAQMD staff is reconunending using the current SCAQI.ID emission factor
for refueling.
First, 100% of refueling vehicles would not be equipped with Phase II ORVR, as
apparently assumed by BAAQMD and the Applicant.
Second, it is generally understood that CARB's 2013 revised controlled gasoline
emission factor for Phase II refueling with ORVR, which the BAAQMD and Applicant
apparently relied on, is a gross underestimate. The South Coast Air Quality Management
District (SCAQMD) recently reviewed the CARB revised 2013 gasoline dispensing emission
factors and concluded that the proposed Phase II ORVR refueling emissions factor of 0.021
lb/1000 gal is a gross underestimate that was not based on any measurements or other
empirical evidence. SCAQMD concluded:28
CARB's revised emission factor for refueling of ORVR vehicles is calculated assuming that the
ORVR system and the Phase H EVR system work consecutively in series to control vapor
emissions, allowing a compounding control efficiency of 99-75 percent from Moth control
equipment. However, there is no empirical evidence supporting the assumption that all the vapors
escaping from the ORVR system are directed to the filipipe and can be captured by the Phase U
EVR system.
Thus, the SCAQMD substituted 0.32 lb/1000 ga1,29 the original CARB estimate, yielding a
refueling emission factor of 0.321bs/1000 gal and a vent emission factor of 0.491b/1000 ga1.30 In
comparison, we used a vent emission factor of 0.581b/1000 gal.31
27 SCAQMD, Proposed Amended Rule 1401—New Source Review of Toxic Ai Contaminants, August
2017, Table 2. Exhibit 2.
28 Ibid,
29 Ibid.
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Non-ORVR vell icl es
Refueling — Phase
":a
I
Iiuncanged
I
from Current
;71emission
ORVvehicles
factor)
*SCAQ1D staff is committed to continue working ttrith CARR staff on the refueling emission factor for Phase II
EVR with OR%'R vehicles. Until then; SCAQMD staff is reconunending using the current SCAQI.ID emission factor
for refueling.
First, 100% of refueling vehicles would not be equipped with Phase II ORVR, as
apparently assumed by BAAQMD and the Applicant.
Second, it is generally understood that CARB's 2013 revised controlled gasoline
emission factor for Phase II refueling with ORVR, which the BAAQMD and Applicant
apparently relied on, is a gross underestimate. The South Coast Air Quality Management
District (SCAQMD) recently reviewed the CARB revised 2013 gasoline dispensing emission
factors and concluded that the proposed Phase II ORVR refueling emissions factor of 0.021
lb/1000 gal is a gross underestimate that was not based on any measurements or other
empirical evidence. SCAQMD concluded:28
CARB's revised emission factor for refueling of ORVR vehicles is calculated assuming that the
ORVR system and the Phase H EVR system work consecutively in series to control vapor
emissions, allowing a compounding control efficiency of 99-75 percent from Moth control
equipment. However, there is no empirical evidence supporting the assumption that all the vapors
escaping from the ORVR system are directed to the filipipe and can be captured by the Phase U
EVR system.
Thus, the SCAQMD substituted 0.32 lb/1000 ga1,29 the original CARB estimate, yielding a
refueling emission factor of 0.321bs/1000 gal and a vent emission factor of 0.491b/1000 ga1.30 In
comparison, we used a vent emission factor of 0.581b/1000 gal.31
27 SCAQMD, Proposed Amended Rule 1401—New Source Review of Toxic Ai Contaminants, August
2017, Table 2. Exhibit 2.
28 Ibid,
29 Ibid.
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Third, all of the various estimates of gasoline station VOC emissions are based on either
no actual measurements or very few measurements, but rather assume theoretical control
efficiencies that have not been demonstrated in the field. Recent research published after
CARB's, BAAQMD's, SCAQMD's, Safeway's, and our initial cancer risk analyses demonstrate
that they all significantly underestimate VOC and benzene emissions, based on substantial
actual measurements at two gas stations. This research, published in a refereed scientific
journal, concludes as follows32
We present unique data on vent enaissioiis from u5 rs at two gas sta-
tions. Emissions can be compared to vent losses :assumed by CAPCOA
(GWCOA, 1997). For a gas station with Stage I and 11 vapor recovery tech-
nologvr and a P..rV valve on the vent pipe of the UST (Scenario 6ii), the
OWCOA study assumed loading losses of 0.081 and breathing losses of
0.025 lb;.ltgal dispensed. `rhe total loss ofgasoline through the vent pipe
is the sum of the two and amounts to a vent emission factor Lrvva=
0.106 lb//gal. Based on actual naeasurelr,ents in two fully functioning
US gas stations, we obtained LF,,, t values of 1.I lb/I(gal for GS -MW and
1.7 lb,rkgal for GS -NW, more than one order of magnitude higher than
the CAf COA estimate. While the difference between our measurements
and the CAi1COA estimates may appear surprising, it is important to con-
sider that the OWCOA estimates are based on relatively Few measure-
ments and some unsupported assumptions (Aerovironnaent, 199,1),
particularly with regard to uncontrolled emissions due to equipment fail-
ures or defects (Appendix A-5 (CM-1COA, 1$99))).
We assumed vent VOC emissions of 0.53 lb VOC/1000 ga1.33 Safeway and BAAQMD
assumed vent VOC emissions of 0.45 lb VOC/1000 ga1.34 As benzene emissions are directly
proportional to VOC emissions (i.e., calculated by multiplying VOC emissions by the fraction of
benzene) and all parties assumed the same benzene content in gasoline, 0.0031b/lb VOC, we
underestimated vent benzene emissions by about a factor of 2, and BAAQMD and Safeway
underestimated vent benzene emissions by about a factor of 3, based on the Hilpert et al. study.
Assuming our estimate of spillage VOC emissions is accurate, we underestimated total facility
30 Vent emission factor = loading + breathing + Phase 11 refueling = 0.15 + 0.024 +0.32 = 0.494 lb/1000 gal.
31 Vent emission factor = loading + breathing + Phase II refueling = 0.08 + 0.42 + 0.03 = 0.53 lb/1000 gal.
32 M. Hilpert, A. M. Rule, B. Adria -Mora, and T. Tiberi, "Vent Pipe Emissions from Storage Tanks at Gas
Stations: Implications for Setback Distances," Science of the Total Environment, v. 650, (2019): 2239-2250
(available online September 24, 2018). Exhibit 3.
33 Vent VOC emissions assumed by appellants: tank filling + vehicle fueling + breathing loss = 0.08 + 0.42
+0.03 = 0.53 lb VOC/1000.
3410/10/18 Rutan Letter, Exhibit A, BAAQMD Evaluation Report, pdf 32. Refueling VOC emissions =
[(5695 lb VOC/yr)/(8500 x103 gal/yr)10.67 = 0.45 lb VOC/103 gal.
24-12
10
benzene emissions by a factor of 2.35 Assuming the BAAQMD's and Safeway's estimate of.
spillage VOC emissions is accurate, they underestimated total facility benzene emissions by a
factor of 3.36
The underestimate in benzene emissions can be used to revise Safeway's estimated
cancer risk. Safeway's revised HRA reported a total 30 -year residential cancer risk of 6.1 per
million. Of this total, 32% or 1.94 per million, is due to benzene emissions from fuel
evaporation37 If we apply the most recent emission data for vent emissions from Hilpert et al.,
we estimate that total VOC emissions would be 2.5 times greater than current ARB/CAPCOA-
recommended emission factors. This would increase the portion of the cancer risk due to
benzene from 1.94 to 4.85 per million and the total 30 -year residential cancer risk from 6.1 per
million to 10 per million.38 A cancer risk of 10 per million is significant. Thus, by correcting
Safeway's analysis to account for its substantial underestimate in benzene emissions, the cancer
risk to nearby residents is significant.
The actual cancer risk would be substantially higher for four reasons. First, both
Safeway and appellants assumed the benzene content of gasoline is 0.003 lb/1000 gallons. The
current proposed benzene content is 0.0455 lb/ ga1.39 This would increase Safeway's residential
cancer risk to 15 per million. Second, both HRAs are based only on benzene. Gasoline vapors
contain other carcinogens, including ethyl benzene, formaldehyde, naphthalene, and
acetaldehyde 40 Naphthalene, for example, is a more potent carcinogen than benzene, with a
cancer unit risk value of 3.4 E-5 ug/m3)-1 compared to 2.9 E-5 ug/m3)-1 for benzene 41 Third, this
revision based only on benzene excludes the increase in cancer risk from adjusting the exposure
duration to 70 years (a 19% increase) and the increase from using the correct DPM emissions
from cars and heavy -heavy-duty trucks, discussed elsewhere in these comments. Fourth, the
omission of benzene from hose permeation and the inclusion of much higher benzene emissions
from non-ORVR vehicles would further increase risk. Fifth, none of the HRAs included the
35 Benzene underestimate based on Fox/Kapahi VOC emissions: [(1.4 + 1.7/2) + 0.42/0.95] =1.97/0.95 =
2.07.
36 Benzene underestimate based on BAAQMD/Safeway VOC emissions: [(1.4 + 1.70/2) + 0.45/0.67] = 3.0.
3710/10/18 Rutan Letter, 10/10/18 Memo from James A. Reyff, Illingworth & Rodkin, Inc, to Natalie
Maffei, Albertsons Companies, Re: Safeway Fuel Center Health Risk Assessment—Updated Modeling
Results Using U.S. EPA's AERMOD Dispersion Model, Table 1, pdf 19.
38 Revised 30 -year residential cancer risk =1.06 + 1.66 + 1.38 + 0.03 + 3(1.94) = 9.95 per million, which
rounds up to 10 per million.
39 SCAQMD, August 2017, Table 3: current speciation = 0.30%; proposed speciation = 0.455%.
40 SCAQMD, August 2017, Table 3 and BAAQMD's CEQA Guidelines (BAAQMD, California
Environmental Quality Act Air Quality Guidelines, May 2017),at p. 5-14 ("TAC emissions were evaluated
for only those toxic compounds found in diesel or gasoline fuel including diesel PM, benzene,
ethylbenzene, acrolein, etc."); available at: http://www.baagmd.gov/-/media/files/planning-and-
research/cepa/cega guidelines _may20l7-pdf.pdf?la=en.
41 OEHHA Hot Spots Unit Risk and Cancer Potentcy Values; available at:
httl2s://oehha.ca.gov/media/CPFs042909.pdf.
24-13
11
increase in cancer risk from increased traffic in the local area to access the gas station. These
changes would increase Safeway's estimated residential cancer risk of 6.1 per million
significantly above the 10 per million cancer significance threshold estimated here, based only
on adjusting benzene exposures. Thus, cancer risks from the proposed gas station are highly
significant.
5.2. Setback Distances
We relied on CARB's 2005 Air Quality/ and Land Use Handbook to confirm safe setback
distances between the proposed gas station and nearby sensitive receptors to confirm our HRA
results. The responses to comments argue that recommendations in this handbook42 are
"outdated" because they were developed using emission factors developed in 1999 and since
then, advancements have occurred that would reduce emissions.43 However, Hilpert et al.'s
recent study, based on actual measurements, concludes the opposite. The Hilpert et a1. study
concluded that "current CARB setback distances might be adequate for gas stations in
California but less so for the other 49 US states." Hilpert et al's AERMOD modeling identified
exceedances of the 1 -hour acute REL for benzene at a distance greater than the 300 ft setback
recommended in the CARB guidance. They concluded that "modeled exceedance of the
OEHHA acute REL in the winter season is already of concern, because that REL was developed
for once per month or less exposure."44
42 CARB, Air Quality and Land Use Handbook; A Comnutnity Health Perspective, April 2005, p. 31; available at
htto://www.arb.ca.gov/ch/handbook.Xcif.
43 Responses, pp. 1-2.
44 Hilpert et al. 2019, p. 2248.
24-14
12
EXHIBIT 1
24-15
From: Lakes Support <support c weblakes.com>
Date: Wed, Oct 17, 2018 at 11:31 AM
Subject: RE: MM5 Data Request for Quote I MET1812984
To: ray.kapahi(a;gmail.com <ray.kapahi2gmail.com>
Cc: Lakes Support <supporta;weblakes.com>
Ray,
Thank you for your email. I'm familiar with the order you're referencing, but that description did
not come from us. We have a standard document provided to customers who request more
information about our WRF data processing routines. While WRF is different from MM5 (which
is what your order was for), neither model as we have them set up are utilizing direct input of
station observations. Station data may be a component of the gridded data which serves as input
to these models, but it is not a direct step.
Note: The information contained in this e-mail is for clarification ptoposes only. GI'e do not assume any responsibility or
liability, explicitly or implied, for its accuracy.
Cheers,
Michael T. Hammer, CCM I Senior Product Specialist
support (cuwebIakes.coin
Lakes Environmental Software
www.webLakes.com I TwitterI Facebook I Linkedln
Sofrivare Solutions I IT Solutions I Training I Services
Upcoming courses in Dubai, UAE; Mexico City, DF and more! Click here to see our training schedule.
CONFIDENTIALITY NOTICE: Information contained in this communication is confidential and privileged proprietary
information for business use purposes only. Unauthorized use, distribution, copying or disclosure is prohibited. If you received
this communication in error. please contact the sender immediately. Thank you.
From: KapahiR <ray U ahi a)n ail.com>
Sent: Wednesday, October 17, 2018 11:19 AM
To: Lakes Software <Lmfofweblakes.com>
Subject: Re: MM5 Data Request for Quote I MET1812984
Julie,
Thanks Julie. I am handling a case for Sonoma County where the applicant (Illingworth &
Rodekin) refers to a met data set developed by Lakes. Their description differs from your
description....
The Weather- Research and Far-ecasting ("WRF") grid model was used to develop a 5 -year
data set (2013 through 2017) for meteorological conditions at the Project site. The WRF model
pulls in observations and archived meteorological model data from the region around the
24-16
Project site,, and uses the same physical equations that are used in tiveather forecasting to model
the historical weather conditions at the specific project location. Development of this data set
was performed by Lakes Environmental using the WRF model and the MMY program to process
data for input to the AERMOD meteorological data preprocessor, AERMET
The above description indicates that data from stations around the project site were used to
develop the met data set. So, is this an accurate description of the met data set developed by
Lakes using the WRF model?
Thanks Julie.
Ray
On Wed, Oct 17, 2018 at 5:42 AM Lakes Software <infoc weblakes.com> wrote::
Dear Ray,
Thank you so much for your inquiry. It's always good to hear from you!
Our MM5 process does not include direct input of local station data; input data to the model are
based on global reanalyzed data which is a computational analysis performed on a combination
of station observations, upper air soundings, and satellite data.
I've gone ahead and sent your quote through. If you have any additional questions, just let us
know.
Have a wonderful day!
Kindest regards,
Julie Swatson I Senior Sales Associate
office: 519.746.5995 1 fax: 519.746.0793
Lakes Environmental Software
www.webLakes.com I Twitter I Facebook I LinkedIn
Software Solutions I IT Solutions I Training I Services
Upcoming courses in Dubai, UAE; Orlando, FL; Mexico City and more! Click here to see our
training schedule.
H Please consider the environment before printing this email
24-17
I * IV
4C 1 4 IN I I bpi
24-18
SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT
Draft Staff Report
Proposed Amended Rule 1401— New Source Review of Toxic Air
Contaminants
August 2017
Deputy Executive Officer
Planning, Rule Development, and Area Sources
Philip M. Fine, Ph.D.
Assistant Deputy Executive Officer
Planning, Rule Development, and Area Sources
Susan Nakamura
Planning and Rules Manager
Planning, Rule Development, and Area Sources
Jillian Wong, Ph.D.
Authors: Kalam Cheung, Ph.D. - Air Quality Specialist
Mike Morris — Program Supervisor
Technical Assistance: Jack Cheng—Air Quality Specialist
Danny Luong — Senior Enforcement Manager
Ian MacMillan — Planning and Rules Manager
Victoria Moaveni —Program Supervisor
Charlene Nguyen — Air Quality Inspector
Reviewed by: William Wong — Principal Deputy District Counsel
Barbara Baird — Chief Deputy District Counsel
24-19
SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT
GOVERNING BOARD
Chairman: DR. WILLIAM A. BURKE.
Speaker of the Assembly Appointee
Vice Chairman: BEN BENOIT
Mayor Pro Tem, Wildomar
Cities of Riverside County
MEMBERS:
MARION ASHLEY
Supervisor, Fifth District
County of Riverside
JOE BUSCAINO
Councilmember, 15th District
City of Los Angeles Representative
MICHAEL A. CACCIOTTI
Mayor, South Pasadena
Cities of Los Angeles County/Eastern Region
SHEILA KUEHL
Supervisor, Third District
County of Los Angeles
JOSEPH K. LYOU, Ph. D.
Governor's Appointee
LARRY MCCALLON
Mayor Pro Tem, Highland
Cities of San Bernardino County
JUDITH MITCHELL
Councilmember, Rolling Hills Estates
Cities of Los Angeles County/Western Region
SHAWN NELSON
Supervisor, Fourth District
County of Orange
DR. CLARK E. PARKER, SR.
Senate Rules Committee Appointee
DWIGHT ROBINSON
Councilmember, Lake Forest
Cities of Orange County
JANICE RUTHERFORD
Supervisor, Second District
County of San Bernardino
EXECUTIVE OFFICER:
WAYNE NASTRI
24-20
TABLE OF CONTENTS
BACKGROUND...........................................................................................................................1
PUBLIC PROCESS AND OUTREACH EFFORTS................................................................. 2
PROPOSED AMENDMENTS TO RULE 1401......................................................................... 2
SPRAY BOOTHS
2
GASOLINE DISPENSING FACILITIES.............................................................................................. 8
LIST OF APPLICABLE TOXIC AIR CONTAMINANTS..................................................................... 19
AFFECTED INDUSTRIES........................................................................................................ 22
SOCIOECONOMIC ASSESSMENT....................................................................................... 23
CALIFORNIA ENVIRONMENTAL QUALITY ACT ANALYSIS ..................................... 24
DRAFT FINDINGS UNDER CALIFORNIA HEALTH AND SAFETY CODE SECTION
40727............................................................................................................................................. 24
COMPARATIVE ANALYSIS................................................................................................... 25
APPENDIX A - U.S. EPA GUIDANCE ON REMOVING STAGE II GASOLINE
REFUELING VAPOR RECOVERY PROGRAMS FROM STATE IMPLEMENTATION
PLAN............................................................................................................................................ 27
APPENDIX B - COMMENTS AND RESPONSES................................................................ 29
24-21
BACKGROUND
Rule 1401 — New Source Review of Toxic Air Contaminants (Rule 1401) was adopted in June
1990 and establishes health risk thresholds for new or modified permitted equipment or processes.
Under Rule 1401, the health risk assessment conducted for new or modified permit units must not
exceed a maximum individual cancer risk of one in one million, a cancer burden of 0.5, a chronic
hazard index of one, and an acute hazard index of one. The methodology used to estimate health
risks for SCAQMD's toxic regulatory program, including Rule 1401, is based on guidance from
the Office of Environmental Human Health Assessment (OEHHA). OEHHA's Risk Assessment
Guidelines are incorporated in the South Coast Air Quality Management District's (SCAQMD)
Risk Assessment Procedures, which are required for implementing Rules 1401, 1401.1 and 212.
The current version of the SCAQMD Risk Assessment Procedures is Version 8.0.
In March 2015, OEHHA revised its Risk Assessment Guidelines' (2015 OEHHA Guidelines) to
incorporate requirements from the Children's Health Protection Act of 1999 (SB 25) which
included the addition of child specific factors that increased the estimated cancer risk for long-
term exposures for residential and sensitive receptors. The result is an increase in the estimated
cancer risk of about 2.3 times, and higher for certain toxic air contaminants that have multiple
exposure pathways such as inhalation, ingestion, and dermal. The 2015 OEHHA Guidelines do
not change the toxic emission reductions already achieved by facilities in the South Coast Air
Basin (Basin). The 2015 OEHHA Guidelines represent a change in the methodologies and
calculations used to estimate health risk based on the most recent scientific data on exposure,
childhood sensitivity, and breathing rates.
At the June 5, 2015 meeting, the SCAQMD Governing Board adopted amendments to Rule 1401
and incorporated the 2015 OEHHA Guidelines into SCAQMD's Risk Assessment Procedures
(Version 8.0)2. SCAQMD staff evaluated permits received between October 1, 2009 and October
1, 2014 and found that most sources would not be required to install new or additional pollution
controls as a result of the 2015 OEHHA Guidelines. The SCAQMD staff had concluded that based
on an initial screening in June 2015, that some spray booths may have difficulties meeting the Rule
1401 risk thresholds using the 2015 OEHHA Guidelines so additional analysis was needed to
better understand potential permitting impacts for spray booths. In addition, time was also needed
to better assess and understand the impacts from gasoline dispensing facilities before use of the
2015 OEHHA Guidelines, and updates to emission factors and speciation profiles for gasoline
dispensing facilities that the California Air Resources Board (CARB) was recommending.
Therefore, provisions were included in the June 2015 amendment to Rule 14013 to allow spray
booths and retail gasoline transfer and dispensing facilities to continue to use the then current
' Available on the internet at https://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-
manual-preparation-health-risk-0
2 SCAQMD's Risk Assessment Procedures for Rules 1401 and 212 (Version 8.0) can be found here:
littL)://www.aqiiid.gov/does/default-soui-ce/planiiiriv/risk-assessment/riskassprociunt e15.pdf and Attachment M
can be found here: http://www.agmd.gov/docs/default-source/permitting* attachment-m.pdf.
3 SCAQMD's June 2015 Staff Report for Proposed Amended Rules 212 — Standards for Approving Permits and
Issuing Public Notice, 1401—New Source Review of Toxic Air Contaminants, 1401.1—Requirements for New
and Relocated Facilities Near Schools, and 1402 — Control of Toxic Air Contaminants fi-om Existing Sources,"
can be found here: http://www.agmd.�zov/docs/default-source/Agendas/GoverninL,-Board12015/2015-iunl-
028.pdf?sfvrsn=9
24-22
SCAQMD Risk Assessment Procedures (Version 7.0)4 to calculate the cancer risk until SCAQMD
staff returns to the Board with specific regulations and/or procedures for these industries.
Staff has since completed the review of analyzing potential permitting impacts for spray booths
and gasoline dispensing facilities. The results of the analysis is presented below under the section
Proposed Amendments to Rule 1401. As discussed later in this staff report, implementation of the
2015 OEHHA Guidelines are expected to have minimal impacts to new or modified spray booth
or gasoline dispensing facilities. As a result, Proposed Amended Rule 1401 will require these two
source categories to begin using the SCAQMD's Risk Assessment Procedures (Version 8.1) which
incorporates the 2015 OEHHA Guidelines for spray booths and gasoline dispensing facilities,
revised emission factors and speciation profiles for gasoline dispensing facilities, and updated
meteorological data. Currently, the SCAQMD's Risk Assessment Procedures (Version 8.0)
requires all other permitted sources to use the 2015 OEHHA Guidelines and no changes except for
updated screening tables using updated meteorological data are proposed for those sources.
PUBLIC PROCESS AND OUTREACH EFFORTS
Development of Proposed Amend Rule 1401 (PAR 1401) is being conducted through a public
process., SCAQMD staff held three working group meetings at SCAQMD Headquarters in
Diamond Bar on June 1, 2017, July 6, 2017, and July 20, 2017. The Working Group is composed
of representatives from businesses, environmental groups, public agencies, and consultants. The
purpose of the working group meetings are to discuss proposed concepts and to work through the
details of staff's proposal. A Public Workshop was held on July 12, 2017.
PROPOSED AMENDMENTS TO RULE 1401
Currently, Rule 1401 allows the use of the previous SCAQMD Risk Assessment Procedures
(Version 7.0) when determining risk for new and modified spray booths (e)(3)(A) and gasoline
dispensing facilities (e)(3)(B). PAR 1401 will remove those provisions and instead require the use
of the proposed SCAQMD Risk Assessment Procedures (Version 8.1) for all new and modified
permitted equipment and processes. Version 8.1 of SCAQMD's Risk Assessment Procedures will
replace Version 8.0 to reflect updates to emission factors for gasoline dispensing facilities, gasoline
speciation profiles and meteorological data. Additionally, PAR 1401 will update the list of toxic
air contaminants subject to the rule.
SPRAY BOOTHS
While previously issued permits are not subject to the proposed amendments to Rule 1401, they
were used to predict potential impacts. To determine if the 2015 OEHHA Guidelines would impact
future spray booth permits, the maximum individual cancer risk calculated in the previous permit
evaluation was multiplied by 2.3 if the materials driving cancer risk had no multipathway factor
(including most volatile organic compounds) or multiplied by six if the material driving cancer
risk had a multipathway factor (including most toxic metals). The increase in the estimated cancer
risk for a residential receptor is 2.3 times higher with the 2015 OEHHA Guidelines. If the receptor
4 SCAQMD's Risk Assessment Procedures for Rules 1401, 1401.1 and 212 (Version 7.0) can be found here:
http:,//www.agmd.gov/docs/default-source/plannin�—,/risk-assessmenth•isk-assessment-procedures-v-7.pddf and
Attachment L can be found here: http://www.agmd.gov/docs/default-source/planning/risk-
ass essment/attachment-I.pdf.
24-23
is a worker there is generally no change in the estimated health risk. As a conservative approach,
it is assumed that these permits had a residential receptor.
If the risk remained below the Rule 1401 risk thresholds of either 1 in -one -million without Best
Available Control Technology for Toxics (T-BACT), or 10 in one million with T-BACT, then
there would be no additional pollution controls required, and no permitting impact. If the
calculated risk was higher than Rule 1401 thresholds, then it was deemed that a similar future
spray booth permit could potentially be impacted. The objectives of the analysis were to answer
the questions if spray booths were permitted with estimated health risks reflecting the 2015
OEHHA Guidelines: (1) would future spray booths that were not required to install pollution
controls, potentially need to install pollution controls; or (2) would future spray booths that were
required to install pollution controls, potentially need to upgrade pollution controls.
Analysis of Spray Booths
Staff evaluated spray booth permits issued from October 1, 2009 through October 1, 2014. Over
the five-year permitting period, SCAQMD staff processed approximately 1,400 new or modified
permits for spray booths. Out of the 1,400 spray booth permits, staff conducted a detailed review
of a subset of 327 permits, which were randomly chosen. This sample size was selected to provide
a 95 percent confidence level and a 5 percent margin of error in the analysis. Staff reviewed
permit applications to better understand:
• Industry type and applicable coating rule(s);
• Compound(s) driving the carcinogenic risk; and
• Maximum individual cancer risk
Out of the 327 permits reviewed, automotive finishing accounted for almost one third of the
applications. Wood coatings and other coatings each contributed to 23 percent of the applications,
followed by metal coatings and aerospace coatings. Overall, the distribution of the industry type
was very similar between the subset of reviewed permits and all the spray booth permits issued
over the five-year period, indicating that the universe of spray booth application was well
represented by the subset sample as indicated by Figure 1 below.
24-24
40
35
30
25
c
QJ 20
a
15
10
5
0
Aerospace Metal Coatings Wood Coatings Automotive Other Coatings
Coatings Refinishing
Figure 1: Industry Type Breakdown of Spray Booth Permit Applications
The spray booths can be categorized into two groups: with or without T-BACT. Figure 2 provides
an overview of the potential impacts of the 2015 OEHHA Guidelines on spray booths. Majority
of the spray booths (277 of 327) are not equipped with T-BACT, while 50 of the 327 spray booths
are equipped with T-BACT. More details about the potential impacts on the two types of spray
booths are discussed below.
Potential Impact
(without T-BACT), 40
pact (with i-BACT),
48
Figure 2: Potential Impacts of 2015 OEHHA Guidelines on Spray Booths
24-25
Impacts on Spray Booth Applications with T-BACT
Of the 327 permits reviewed, 50 were permitted with T-BACT. Of those 50 permits with T-BACT,
48 spray booths would have an estimated cancer risk that remained below the threshold of 10 in
one million with the application of the 2015 OEHHA Guidelines. Among these spray booths, most
of them use coatings containing hexavalent chromium or other metals. Thus, if 48 similar spray
booths were permitted in the future using the proposed SCAQMD Risk Assessment Procedures
(Version 8.1) that incorporates the 2015 OEHHA Guidelines, no additional pollution controls are
expected.
Two spray booths had an estimated cancer risk above 10 in one million with the use of the 2015
OEHHA Guidelines. These two spray booths use aerospace coatings containing hexavalent
chromium, and were permitted with high efficiency particulate air (NEPA) filters with an
efficiency of 99.999 percent, which satisfies the T-BACT requirement. The permitted cancer risk
was kept below 10 in a million with limits on the maximum allowable usage of hexavalent
chromium and ethyl benzene. If these two spray booths were permitted using the proposed
SCAQMD Risk Assessment Procedures (Version 8.1) which incorporates the 2015 OEHHA
Guidelines, the cancer risk would exceed the threshold of 10 in one million assuming the same
throughput and emission control technology (TEPA filters) are used. Thus, a new spray booth
application with the same operating conditions as these two spray booths would have to either
reduce their throughput or use a more effective control technology. An ultra-low penetration air
(ULPA) filter provides a removal efficiency of 99.9999 percent or better, and is commercially
available with a comparable cost as the HEPA filter. With the use of an ULPA filter, throughput
would not need to be reduced. Nonetheless, a filter with a higher efficiency will likely increase
the pressure drop across the filter. Depending on the design of the air system, a stronger fan/blower
might be needed to accommodate a more efficient filter.
Impacts on Spray Booth Applications without T-BACT
Of the 327 permits reviewed, 277 are permitted without T-BACT. Staff estimates that with the
application of the 2015 OEHHA Guidelines the estimated cancer risk for 237 (86 percent)
permitted spray booths would remain below a health risk of 1 in one million so no further action,
such as the addition of pollution controls or changes to the type or amount of materials identified
in the permit, would be expected. These types of permit applications would not be impacted by
incorporating the 2015 OEHHA Guidelines in the proposed SCAQMD Risk Assessment
Procedures (Version 8.1) because the coatings applied have low or no toxics content.
Of the 277 spray booths without T-BACT, 40 spray booths (14 percent) exceeded the cancer risk
threshold of 1 in one million when the 2015 OEHHA Guidelines were applied. An in-depth
analysis was conducted on the permits issued for these 40 spray booths to better understand the
volume and the content of toxic air contaminants in the coatings used. Four spray booths were
found to be no longer in service and are not included in the analysis below, leaving 36 permits for
spray booths analyzed. Staff collected safety data sheets, usage records, contacted coating
suppliers, or conducted site visits to examine the potential impact of the 2015 OEHHA Guidelines.
Among the 36 spray booths that are in operation, ethyl benzene was the most prevalent toxic air
contaminant used in coatings with 72 percent of the permits for spray booths use coatings with
ethyl benzene. Formaldehyde is the next most common toxic air contaminant used in coatings,
24-26
representing 8 percent of the permits for spray booths. For the other permits, the formulations had
multiple toxic air contaminants, including ethyl benzene and formaldehyde (8 percent), ethyl
benzene and nickel (6 percent), as well as ethyl benzene and others (6 percent).
As discussed in more detail below, the 36 permits for spray booths are not expected to be impacted
by the 2015 OEHHA Guidelines because the facilities are either no longer using toxic air
contaminants, the actual usage of materials containing toxic air contaminants is much lower than
permitted levels, or the amount of toxic air contaminants assumed in the permit is higher than the
actual amount in the material used. The results of the in-depth analysis is illustrated in Figure 3
below.
Permitted Spray Booths Without T-BACT — Use of Materials With Toxic Air Contaminants
Based on interviews with owner or operators with permitted spray booths, staff found that for 10
of the 36 permits for spray booths, the owner or operator switched coatings and are currently using
coatings that do not contain toxic air containments. In some cases, the facility had opted to utilize
a new coating while in the remaining cases, the coating had been reformulated. Reformulated
coatings typically replace the mineral spirits that contains trace quantities of ethyl benzene with a
hydrotreated petroleum distillate that performs the same function but does not contain ethyl
benzene. Thus, it is expected that a considerable fraction of owners or operators that are applying
for future permits for spray booths will be selecting coatings that do not contain. toxic air
contaminants as coatings that do not contain toxic air contaminants are available. It is assumed
that for the 10 permitted spray booths that originally were using coatings with toxic air
contaminants, that in the future these permit applications would not be impacted by incorporating
the 2015 OEHHA Guidelines in the proposed SCAQMD Risk Assessment Procedures (Version
8.1) because operators are already making the decision to use coatings that do not contain toxic air
contaminants.
Permitted Spray Booths Without T-BACT —Actual Material Usage
Based on interviews and site visits with owner and operators, staff found that the permitted usage
of coatings was considerably higher than the actual usage in 16 of 36 permits for spray booths
reviewed (25 percent). In many cases, the facility is given a maximum allowable limit on the
number of gallons for the overall use and a maximum allowable limit on the number of gallons
that can be used that contain a toxic air contaminant. Because the spray booths use multiple
coatings within the same booth and most coatings do not contain a toxic air contaminant, the
facility may use close to their overall use limit but not approach their limit for coatings that contain
toxic air contaminants. Because their actual usage is considerably lower than their maximum
allowable usage limit for specific coatings with toxic air contaminants, a lower permitted usage
for specific coatings with toxic air contaminants will not impact their operations. By establishing
maximum usage limits for coatings with toxic air contaminants that are closer to anticipated actual
usage, it is expected that for the 16 permitted spray booths that in the future these permit
applications would not be impacted by incorporating the 2015 OEHHA Guidelines in the proposed
SCAQMD Risk Assessment Procedures (Version 8.1) because operators can accept a lower
permitted usage limit for materials with toxic air contaminants.
Permitted Spray Booths Without T-BACT — Toxic Air Contaminant Content in Safeo) Data
Sheet
24-27
Based on interviews with owner or operators and coating formulators, staff found that for 10 of
the spray booths, the Safety Data Sheet had overstated the quantity of toxic air contaminants in
their coatings. Safety Data Sheets list the range (in percent by weight) of toxic air contaminants
present in the coating formulation. In many cases the formulated coating lists the ethyl benzene
content as between 0.5 and 5 percent. However, based on discussions with the coating formulator,
the actual ethyl benzene content for the formulated product is actually between 0.2 and 2.5 percent.
If these spray booths were to apply for new permits under the proposed SCAQMD Risk
Assessment Procedures (Version 8.1), they might consider migrating to reformulated coatings /
new coatings with lower or no ethyl benzene content. Alternatively, manufacturers might update
the Safety Data Sheet to provide a more accurate estimate with products using ethyl benzene. By
either using a more accurate percentage of toxic air contaminant in the coating formulation or
using a coating with lower or no ethyl benzene, it is expected that for the 10 permitted spray booths
that in the future these permit applications would not be impacted by incorporating the 2015
OEHHA Guidelines in the proposed SCAQMD Risk Assessment Procedures (Version 8.1).
Summary of Spray Booth Analysis
Based on the detailed review of 327 spray booth permit applications, the implementation of the
2015 OEHHA Guidelines in the proposed SCAQMD Risk Assessment Procedures (Version 8.1)
will result in no impact for 99 percent of spray booth permits. Figure 3 below summarizes staff's
findings for spray booths that were permitted without T-BACT. For spray booths that were
permitted without T-BACT, it is expected that in the future permit applicants will either select a
coating with no toxic air contaminants, use products that provide more accurate estimates of toxic
air contaminants in the Safety Data Sheet, or accept a lower usage limit for coatings that contain
toxic air contaminants rather than install T-BACT.
Using New Producl
(No Longer Using
Toxic Air
Contaminant), 10
Safety Data Sheet
verstated Toxic Air
ntaminant (Amount
of Toxic Air
;ontaminant Listed
Does Not Reflect
actual Amount), 10
Figure 3: Summary Findings for 36 Spray Booths without T-BACT
Table 1 provides a summary findings for spray booths. Approximately 1 percent (two of the 327)
of spray booth permits may need to use a high efficiency filter media such as ULPA filters, or
consider reducing their throughput if the 2015 OEHHA Guidelines are utilized. For facilities that
were permitted without T-BACT, it is expected that no additional pollution controls would be
needed using the 2015 OEHHA Guidelines. Therefore, with a 95 percent confidence level, it is
expected that approximately 1 percent of new spray booth permit applications will require
24-28
additional pollution control equipment if the 2015 OEHHA Guidelines are utilized. With
SCAQMD receiving, on average, 280 spray booth permit applications annually, approximately
two spray booth permits annually could require higher level of air pollution controls. The expected
additional air pollution control would be the replacement of NEPA filters with ULPA filters. It is
concluded that the impact of the 2015 OEH14A Guidelines are minimal on spray booth permits.
Therefore, staff recommends removing the exemption and referencing the proposed SCAQMD
Risk Assessment Procedures (Version 8.1) for spray booths.
Table l: Summary Findings for Spray Booths with T-BACT
Total number of spray booths reviewed
327
Spray booths without T-BACT where the cancer risk with the 2015
OEHHA Guidelines would be:
• < 1 in one million after initial review
237
• < 1 in one million after in-depth review
o Use of materials with toxic air contaminants
10
No
o Actual material usage
16
No
o Toxic air contaminant content in Safety Data Sheet
10
No
o No longer in operation
4
N/A
Spray booths with T-BACT where the cancer risk with the 2015
OEHHA Guidelines would be:
• < 10 in one million
48
No
0 >10 in one million
2
Yes
Percent of spray booth permits that will need T-BACT or upgrades
0.6%
to T-BACT controls out of 327 permits reviewed
GASOLINE DISPENSING FACILITIES
In the amendments to Rule 1401 in June 2015, SCAQMD staff recommended that retail gasoline
transfer and dispensing facilities continue to use the then current SCAQMD Risk Assessment
Procedures (Version 7.0) because additional time was needed to better assess the potential impacts
of the revised speciation profile that the California Air Resources Board (CARB) had provided in
March 2015 and emission data on gasoline dispensing facilities. As part of this rule development
process for PAR 1401, staff evaluated the potential impacts of the revised emission factors and
gasoline speciation profiles and how they could affect new gasoline dispensing facilities combined
with the use of the 2015 OEHHA Guidelines in proposed SCAQMD Risk Assessment Procedures
(Version 8.1).
Gasoline Dispensing Emission Factors
Gasoline dispensing emission factors gasoline speciation profiles for air toxics are developed by
the California Air Resources Board (CARB). In December 2013, CARB revised emission factors
24-29
for gasoline dispensing facilities and are described in CARB's "Revised Emission Factors for
Gasoline Marketing Operations at California Gasoline Dispensing Facilities." (CARB's 2013
Revised Emission Factors). The emission factors were revised for the processes of loading,
breathing, and refueling, and new information was added for hose permeation. The emission factor
for spillage remains unchanged. Each of these emission sources is briefly described below:
i) Loading - Emissions occur when a fuel tanker truck unloads gasoline to the storage
tanks. The storage tank vapors, displaced during loading, are emitted through its vent
pipe. A pressure/vacuum valve installed on the tank vent pipe significantly reduces
these emissions.
ii) Breathing - Emissions occur through the storage tank vent pipe as a result of
,temperature and pressure changes in the tank vapor space.
iii) Refueling - Emissions occur during motor vehicle refueling when gasoline vapors
escape either through the vehicle/nozzle interface or the onboard refueling vapor
recovery (ORVR) system.
iv) Spillage - Emissions occur from evaporating gasoline that spills during vehicle
refueling.
v) Hose Permeation - Emissions caused by the migration of liquid gasoline through the
outer hose material and to the atmosphere through permeation.
One of the updates to the 2013 Revised Emission Factors was to add a new subcategory for
refueling for Phase II fueling for vehicles equipped with ORVR. CARB's previous emission
factors which were adopted in 1999 did not account for vehicles equipped with ORVR. Table 2
presents CARB's 2013 Revised Emission Factors and SCAQMD's proposed controlled gasoline
emission factors for the process of loading, breathing, refueling, spillage and hose permeation.
SCAQMD staff is recommending the use of CARB's Revised Controlled Gasoline Emission
Factors for loading, breathing, spillage and hose permeation. SCAQMD staff, however, is
recommending not to incorporate CARB's 2013 revised emission factors for refueling ORVR
vehicles, but continuing the use of the current SCAQMD emission factor for refueling.
24-30
Table 2: CARB 2013 Revised and SCAQMD Proposed Controlled Gasoline Dispensing
Emission Factors (lbs/1,000 gallon)
*SCAQMD staff is committed to continue working with CARB staff on the refueling emission factor for Phase II
EVR with ORVR vehicles. Until then, SCAQMD staff is recommending using the current SCAQMD emission factor
for refueling.
Refueling Emission Factor for Phase II with ORVR Vehicles
The SCAQMD staff has reviewed the emission factor for refueling, and believes that CARB's
2013 revised emission factors may overestimate the emission reductions from refueling with Phase
II with ORVR vehicles. CARB's approach to derive the refueling emission factor is to apply a 95
percent control efficiency for Phase II enhanced vapor recovery (EVR), and an additional 95
percent control efficiency for ORVR to provide an overall control efficiency for refueling of 99.75
percent. Based on SCAQMD staff's review of the Phase 11 EVR and ORVR technologies, these
two pollution control technologies may not work in series to provide a 99.75 control efficiency.
The technical basis of staff's determination is presented below.
Phase II EVR is a system designed to capture displaced vapors that emerge from inside a vehicle's
fuel tank, when gasoline is dispensed into the tank. As shown in Figure 4, during refueling, vapors
are pulled from the gasoline tank to the underground storage tank for a vehicle that is not equipped
with ORVR that is fueled with Phase H EVR. Currently there are two systems certified for Phase
II EVR: a balance system and a vacuum -assist system. The balance system transfers vapors from
the vehicle and returns them to the underground storage tank based on the pressure differential. A
vacuum -assist system relies on a vacuum to draw vapors from the vehicle fuel tank into the
underground storage tank. CARB requires use of ORVR-compatible Phase II EVR systems that
are designed to sense when an ORVR vehicle is being refueled and reduces the air to liquid ratio
to near zero to avoid compatibility emission effects in the underground storage tank. CARB has
determined that Phase II EVR systems have a control efficiency of 95 percent.
24-31
am
wom
Breathing
• • i
Refueling — Phase 11 with
Non-ORVR vehicles
I
�II II
• , .
Refueling with•
�.
• •'• •
••••les
emission. •
� �
� �
�fY1111�' ► i
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Hose Permeation
*SCAQMD staff is committed to continue working with CARB staff on the refueling emission factor for Phase II
EVR with ORVR vehicles. Until then, SCAQMD staff is recommending using the current SCAQMD emission factor
for refueling.
Refueling Emission Factor for Phase II with ORVR Vehicles
The SCAQMD staff has reviewed the emission factor for refueling, and believes that CARB's
2013 revised emission factors may overestimate the emission reductions from refueling with Phase
II with ORVR vehicles. CARB's approach to derive the refueling emission factor is to apply a 95
percent control efficiency for Phase II enhanced vapor recovery (EVR), and an additional 95
percent control efficiency for ORVR to provide an overall control efficiency for refueling of 99.75
percent. Based on SCAQMD staff's review of the Phase 11 EVR and ORVR technologies, these
two pollution control technologies may not work in series to provide a 99.75 control efficiency.
The technical basis of staff's determination is presented below.
Phase II EVR is a system designed to capture displaced vapors that emerge from inside a vehicle's
fuel tank, when gasoline is dispensed into the tank. As shown in Figure 4, during refueling, vapors
are pulled from the gasoline tank to the underground storage tank for a vehicle that is not equipped
with ORVR that is fueled with Phase H EVR. Currently there are two systems certified for Phase
II EVR: a balance system and a vacuum -assist system. The balance system transfers vapors from
the vehicle and returns them to the underground storage tank based on the pressure differential. A
vacuum -assist system relies on a vacuum to draw vapors from the vehicle fuel tank into the
underground storage tank. CARB requires use of ORVR-compatible Phase II EVR systems that
are designed to sense when an ORVR vehicle is being refueled and reduces the air to liquid ratio
to near zero to avoid compatibility emission effects in the underground storage tank. CARB has
determined that Phase II EVR systems have a control efficiency of 95 percent.
24-31
Figure 4: Phase II Vapor Recovery Underground Tank Captures Displaced Vapors
As shown in Figure 5, an ORVR system captures the gasoline vapors that are displaced during
refueling and stores those vapors in a canister filled with activated carbon. When the vehicle engine
is started, gasoline vapors stored in the canister are purged and burned in the engine. The carbon
bed achieves an average control efficiency of 95% as determined by CARB.
Figure 5: Onboard Refueling Vapor Recovery System Capture Displaced Vapors
Figure 6 provides a more detailed view of the fuel tank and the modified fillpipe on a vehicle
equipped with ORVR. As shown in Figure 6, the ORVR system has mechanisms (i.e. a narrowed
24-32
fillpipe to form a liquid barrier and a mechanical valve at the end of the fillpipe) to prevent vapor
within a vehicle fuel tank from escaping via the fillpipe of the vehicle to the Phase II controls. The
vapor that would have otherwise escaped through the fillpipe to the Phase 11 controls is instead
directed to a carbon canister contained within the vehicle, which is the actual means of emission
control of the ORVR system, to adsorb hydrocarbons contained in the displaced vapor.
ORVR
Canister
Vapors directed
Valve in fillpipe
prevents vapors
from entering the
fillpipe
Figure 6: Detailed View of Fillpipe for Onboard Refueling Vapor Recovery System
CARB's revised emission factor for refueling of ORVR vehicles is calculated assuming that the
ORVR system and the Phase II EVR system work consecutively in series to control vapor
emissions, allowing a compounding control efficiency of 99.75 percent from both control
equipment. However, there is no empirical evidence supporting the assumption that all the vapors
escaping from the ORVR system are directed to the fillpipe and can be captured by the Phase II
EVR system.
To further illustrate that emission reductions from the Phase II EVR system are not compounded,
the United States Environmental Protection Agency (U.S. EPA) has conducted source test studies
according to the Federal Test Procedure. The U.S. EPA tests were conducted using sealed housing
emissions device (SHED), where emissions from both the fillpipe and the on -board canister were
monitored. The U.S. EPA study tested 337 dispensing events, and the results are summarized in a
report published by CARB in 2008 (Table 7)5. The fillpipe and on -board canister emissions
together averaged to 0.25 pounds per 1,000 gallons, suggesting that the revised emission factor
recommended by CARB underestimates the emissions from refueling ORVR vehicles. The table
further shows a standard deviation of 1.15 which indicates the control efficiency of individual
vehicle tested varies significantly from the average emissions of 0.25 pounds per 1,000 gallons.
Additional justifications can be found with the documents U.S. EPA issued on its rule to remove
the federal Stage II program from the State Implementation Plans (SIP) requirements. On July 15,
2011, the U.S. EPA issued a proposed rule titled "Widespread Use for Onboard Refueling Vapor
Recovery and Stage II Waiver." The proposed rule allowed states to consider removing Stage II
vapor recovery requirements when revising their SIPs, due to the national widespread use of
ORVR. Subsequently, U.S. EPA issued the "Guidance on Removing Stage II Gasoline Refueling
Vapor Recovery Programs from State Implementation Plan" in 2012. The Guidance document
provides both policy and technical recommendations for states seeking to remove or phase-out
s Available on the internet at littl2s://www.,irb.ca.gov/vapor/archive/2008,/orvrtestrepoi-tO72408.pdf
24-33
existing Stage II program, based on the premise that the Stage II program would become largely -
redundant due to the widespread use of ORVR.
On the federal level, the control efficiency of Stage II is in the range of 60-75 percent, much lower
than the California Phase II program (95 percent). In addition, in areas where certain types of
vacuum -assist Stage II control systems are used, the limited compatibility between ORVR and
some configurations of this Stage II hardware may result in an area -wide emissions disbenefit.
U.S. EPA's regulation stated that with the widespread use of the ORVR-equipped vehicles, Stage
II programs have become largely redundant control systems with minimal reduction benefits
beyond the ORVR system. SCAQMD and CARB have commented that Phase II EVR are still
needed as discussed in more detail under their comment letters submitted in response to U.S.
EPA's proposed rule. U.S. EPA's guidance does, however provide additional insight regarding
the application of emission reductions from Stage II control systems for vehicles equipped with
ORVR further demonstrating that the control efficiency of the ORVR and/or the Stage II systems
are only applied once to the respective gasoline throughput. See Appendix A for a detailed
discussion.
Additional Refueling Emission Reductions for Phase II with ORVR Vehicles
Although the SCAQMD staff does not believe that it is technically correct to apply an additional
95% control efficiency on the remaining refueling emissions for a vehicle equipped with ORVR,
there is evidence that vehicles equipped with ORVR do have emissions at the fillpipe. A study
conducted by CARB in 20087 measured the gasoline vapor emissions at the vehicle fuel fillpipe
of ORVR vehicles at a gasoline dispensing facility with no Phase II EVR system. Although the
study demonstrated that the majority of the vapors escaping from the ORVR canister is not routed
to the fillpipe, there is a small percentage of vapors that will escape the fillpipe that can be captured
by the Phase II EVR system. As discussed below, the amount of vapors escaping the fillpipe that
can be captured by the Phase II EVR system is much less than the 0.42 lbs/1,000 gallons that
CARB used to estimate emission reductions from Phase II EVR systems for vehicles with ORVR.
The 2008 CARB study was conducted at an "ambient environment" at a gasoline dispensing
facility for a rental vehicle company and based on 58 dispensing events. While the test was
designed to evaluate fillpipe emissions, the study could not capture emissions from the on -board
canister of the ORVR system. Therefore, it does not present total refueling emissions, which
includes emissions from both the fillpipe and the on -board canister for ORVR vehicles. Results
from the 2008 CARB study showed that fillpipe emissions from ORVR vehicles, which represent
the vapors escaping via the fillpipe and not directed to the carbon canister, were 0.043 lb per 1,000
gallons dispensed for summer fuel and 0.094 lb per 1,000 gallons for winter fuel. The low fillpipe
emissions for ORVR vehicles are consistent with the design of the ORVR system, which creates
a seal in the vehicle fillpipe to route vapors to the onboard canister during dispensing. Moreover,
these emissions are a very small fraction of the anticipated emissions escaping from the ORVR
canister, which is approximately 0.42 lbs per 1,000 gallons (5 percent of the uncontrolled emission
factor of 8.4 lbs per 1,000 gallons).
6 Available on the internet at
https://www.regulations.gov/docketBrowser?rpp=50&so=DESC&sb=postedDate&po=0&dct=P S&D=EPA-
HQ-OAR-2010-1076
Available on the internet at bttps://www.arb.ca.gov/vapor/archive/2008/oivrtestreportO72408,pdf
24-34
The SCAQMD staff believes that there is a small amount of vapor that the Phase II EVR system
will control during refueling of an ORVR vehicle. SCAQMD staff has been in communication
with CARB staff regarding the refueling emissions factor. Both agencies agree that additional
time is needed to better understand emission reductions from Phase II EVR for ORVR vehicles.
SCAQMD staff is recommending not to incorporate CARB's 2013 revised emission factor for
Phase II refueling of ORVR vehicles, but to continue the use of SCAQMD's current emission
factor of 0.32 lbs per 1,000 gallons for refueling. Staff is recommending the use of CARB's 2013
emission factors for all other categories (loading, breathing, spillage, and hose permeation). The
SCAQMD staff is committed to continue working with CARB staff to refine the refueling emission
estimates for Phase II controls with ORVR vehicles and will return to the Board with future
revisions to refueling emission factors.
Need for Phase II Enhanced Vapor Recovery with ORVR
Although U.S. EPA has determined that the federal Stage II program had become largely -
redundant due to the widespread use of ORVR, the Phase II requirements are still needed in
California. In 2011, CARB prepared a comment letter$ in response to U.S. EPA's proposed rule
regarding gasoline vapor recovery control of ozone -precursor emissions titled Air Quality:
Widespread Use for Onboard Refueling Vapor Recovery and Stage II Waiver. Included in the
comment letter is an analysis that supports the need for California's Phase II EVR requirements
even with the widespread use of ORVR. It highlights that Phase II EVR is needed for non-ORVR
vehicles to achieve the additional VOC reductions of 14.7 tons per day in the year of 2020, and
8.8 tons per day in the year 2028 and beyond. Also, California's Phase II program includes other
emission control features, such as in -station diagnostics and standards for nozzle liquid retention,
dripless nozzle and spillage, in addition to the control of the vapors displaced during vehicle
refueling. Thus, it achieves greater emission reductions than the federal Stage II program
requirements and the improvement it provides is essential to meeting mandated federal ambient
air quality standards.
Furthermore, the impacts of removing California's Phase II program could be magnified in
disadvantaged communities. Due to the lower socioeconomic status in disadvantaged
communities, the turnover of the fleet is usually lower. Since vehicles manufactured before year
1998 are not equipped with ORVR, disadvantaged communities could have a higher fraction of
non-ORVR vehicles than non -disadvantaged communities, and removal of the Phase II EVR
system would put much of the emission disbenefit in the disadvantaged communities.
In addition to emission factors, CARB has also developed speciation profiles of various toxic air
contaminants. Out of the toxic compounds emitted from gasoline facilities, benzene,
ethylbenzene, and naphthalene have cancer toxicity values. The speciation profiles are different
for vapor and liquid phases of gasoline for benzene, ethyl benzene, and naphthalene. Table 3
presents the current and proposed speciation profile in weight percent for the three toxic air
contaminants. SCAQMD staff recommends using CARB's proposed gasoline speciation profile.
a Available on the internet at
https://www.arb.ca. izov/vapor/carb%20response%20useap%20orvr%20widest)read%20use°/`20nprm.pdf.
24-35
Table 3: Current and Proposed Weight Percent (lbs/1,000 gallon)
Analysis of Permitting Impacts for Gasoline Dispensing Facilities Using SCAQMD Risk
Assessment Procedures Version 8.1
The proposed SCAQMD Risk Assessment Procedures (Version 8.1) has been revised using the
following updated items for gasoline: (1) 2015 OEHHA Guidelines for spray booths and gasoline
dispensing facilities, (2) -emission factors for gasoline dispensing facilities and gasoline speciation
profiles (as discussed earlier), and (3) dispersion model and meteorological data. To assess the
impacts of these updates on future gasoline dispensing facilities, staff evaluated gasoline
dispensing facilities that applied for a new permit (i.e. permit to construct or permit to operate)
from October 1, 2009 through December 31, 2016. If the recalculated risk of a previously issued
permit using the proposed SCAQMD Risk Assessment Procedures (Version 8.1) would be higher
than Rule 1401 thresholds, then it was deemed that a similar future gasoline dispensing facility
permit would potentially be impacted.
Under SCAQMD's Risk Assessment Procedures (Version 7.0), the U.S. EPA's dispersion model
ISCST3 (Industrial Source Complex — Short Term, Version 3) was incorporated in the Hotspots
Analysis and Reporting Program (HARP) software for the health risk assessment. In the most
recent version of HARP (HARP 2), the U.S. EPA dispersion model AERMOD is used to estimate
the concentration of pollutants in place of the previously used ISCST3 model. In addition to the
new dispersion model, the meteorological data used to estimate cancer risk has been updated. It
is SCAQMD's policy to update the meteorological data used for dispersion modeling every three
years. In previous years, the use of SCAQMD collected meteorological data was used exclusively.
However, in the most recent update of meteorological data, it was discovered that the
meteorological data at some SCAQMD sites did not meet the QA/QC criteria for dispersion
modeling. Therefore, the SCAQMD meteorological sites were supplemented with Automated
Surface Observing System (ASOS) sites. Designed to serve meteorological and aviation observing
needs, ASOS sites are located at various airports in the Basin. ASOS data was retrieved from the
National Centers for Environmental Information (https://www.ncei.noaa.govn. Finally, the use of
meteorological correction factors for gasoline dispensing facilities have been removed in favor of
more precise dispersion factors provided for each meteorological station. Additional information
about the updates of the meteorological modeling are included in Appendix VI of SCAQMD's
Risk Assessment Procedures (Version 8.1).
Impacts on New Gasoline Dispensing Facilities
Over the seven-year period, 140 new permits of gasoline dispensing facilities were processed. To
identify gasoline dispensing facilities that would exceed the maximum individual cancer risk of
ten in one million as they are equipped with T-BACT, staff gathered the following data from the
permit applications:
24-36
• Industry type and application type (new, modified, relocated);
• Permitted throughput, usually expressed as million gallons per year;
• Distance to the nearest residential and commercial receptor;
• Location of the gasoline dispensing facilities; and
• Maximum individual cancer risk
Table 4 provides a summary of the permitted annual throughput for the gasoline dispensing
facilities reviewed. Of the 140 new permits, the majority of the applications (64 percent) are
permitted at less than one million gallons per year. They include aboveground storage tanks,
mobile fuelers, as well as underground storage tanks serving commercial (non -retail) operations.
Fifty gasoline dispensing facilities were permitted at an annual throughput above one million
gallons per year. Most of these higher throughput facilities are retail service stations.
Table 4: Annual Throughput of Gasoline Dispensing Facilities
Permitted between 2009 and 2016
<1 90 Aboveground storage tanks,
mobile fuelers, and others
1-3 9 Aboveground storage tanks and
retail gas stations
>3 1 41 1 Retail gas stations
Impacts on New Gasoline Dispensing Facilities Permitted Using a Tier 4 Analysis
Over the seven-year period from October 2009 to December 2016, three of the 140 new gasoline
dispensing facilities had a maximum individual cancer risk above ten in one million based on Tier
2 screening and therefore, the applicant submitted a more refined site specific Tier 4 analysis
(Detailed Risk Assessment) in order to demonstrate compliance with Rule 1401 at the requested
throughput. To estimate the potential impacts on those applications, a percentage change, based
on a comparison between the Tier 2 screening tables of SCAQMD Risk Assessment Procedures
in Version 7.0 and Version 8. 1, was applied. The percentage change is site-specific, depending on
the facility location and distance to receptor. After applying the percentage change, the estimated
health risk for the three gasoline dispensing facilities is expected to decrease and remained below
the threshold of ten in one million. Therefore, it is expected that for new gasoline dispensing
facilities permitted using Tier 4 analysis that in the future these permit applications would not be
impacted by the proposed SCAQMD Risk Assessment Procedures (Version 8.1).
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Impacts on New Gasoline Dispensing Facilities Permitted Using Tier 2 Analysis
The cancer risks for the rest of the permit applications (137 of 140) from 2009 to 2016 were
determined using Tier 2 Screening Risk Assessment. In order to analyze the impacts to these
permits from the use of the 2015 OEHHA Guidelines, staff used the screening tables (Tier 2) in
the proposed SCAQMD Risk Assessment Procedures (Version 8.1) to estimate the cancer risk for
the permits. Using the proposed SCAQMD Risk Assessment Procedures (Version 8.1), 132 of the
137 gasoline dispensing facilities had estimated cancer risks that remained below the Rule 1401
thresholds. Therefore, no impact is expected for 96 percent of the new permit applications, if these
permits were to be processed with the proposed SCAQMD Risk Assessment Procedures (Version
8.1). Five of the 137 facilities had cancer risks that would exceed the threshold. The five facilities
are retail service stations equipped with CARB certified Phase I and Phase II EVR systems, which
are considered to be T-BACT. The five facilities are located in Whitter (Facility A), Burbank
(Facility B), Riverside (Facility C),. Perris (Facility D), and Perris (Facility E), respectively. Table
5 summarizes the potential impacts of the proposed SCAQMD Risk Assessment Procedures
(Version 8.1). Note that for these five facilities, the permitted allowable throughput was based on
Tier 2 Screening Risk Assessment as part of the permitting process. The permit applicants did not
need to proceed to a higher tier (Tier 3: Screening Dispersion Modeling or Tier 4: Detailed Risk
Assessment) for a more refined risk assessment. However, if Facility A, B9, C, D and E were to
apply for a new permit under the proposed SCAQMD Risk Assessment Procedures (Version 8. 1),
their allowable throughput would have decreased by 13%, 16%, 40%, 28% and 22%, respectively.
Table 5: Potential Impacts of the Proposed SCAQMD Risk Assessment Procedures
(Version 8.1)
9 Note that this facility is located within 500 feet of a school and permitted prior to the adoption of Rule 1401.1 -
Requirements for New and Relocated Facilities near Schools. Under SCAQMD Rule 1401.1, the maximum
individual cancer risk shall not exceed one in one million at any school within 500 feet of the toxic -emitting permit
unit at the facility. Therefore, if a facility was to apply for a new or modified SCAQMD permit where Facility B is
located, it would be subject to Rule 1401.1. The maximum individual cancer risk will be limited to less than one in
one million at the school, and the permitted throughput will be substantially lower.
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All retail service stations within SCAQMD's jurisdiction are already equipped with CARB
certified Phase I and Phase II vapor recovery systems to control gasoline emissions. Phase I vapor
recovery refers to the collection of gasoline vapors displaced from storage tanks when cargo tank
trucks make gasoline deliveries. Phase II EVR systems control the vapors displaced from the
vehicle fuel tanks during refueling. In addition, all gasoline is stored underground with valves
installed on the tank vent pipes to further control gasoline emissions. Installation of additional
emission control technology is not economical and very unlikely.
On the other hand, cancer risks decrease substantially with distance. Estimated cancer risks are
higher when the facility is close to the receptor. For one million gallons of gasoline, the residential
maximum individual cancer risk ranges from 2.6 to 5.2 in one million at 25 meters from receptor,
and decreases considerably to a range of 0.31 to 0.76 in one million at 100 meters from the
receptor. Among the five facilities listed in Table 5, the highest cancer risk is observed at Facility
C. Using Facility C as the worst case scenario, the cancer risk calculated using the proposed
SCAQMD Risk Assessment Procedures (Version 8.1) would remain below the threshold for the
same throughput as previously permitted, if the distance between the emission source and the
nearest downwind receptor was 54 meters instead of 41 meters. Thus, retail gasoline dispensing
facilities that would like to be permitted with a relatively high throughput might need to give more
consideration to its site design by positioning the emission source further away from the sensitive
receptor.
Furthermore, while the use of Tier 1 and Tier 2 screening tables are useful to allow most facilities
to demonstrate compliance with Rule 1401 without complicated'dispersion modeling, there are
other more refined modeling options available to applicants such as the use of Tier 3 and Tier 4
analyses. As previously discussed, three of the 140 new applicants demonstrated compliance
through Tier 4 modeling. If the Tier 2 screening risk assessment results in a risk estimate that
exceeds the risk limits or the permit applicant feels that a more detailed evaluation would result in
a lower risk estimate, the applicant has the option of conducting a more detailed analysis using
Tier 3 or 4.
Impacts on Modified Gasoline Dispensing Facilities
Staff also evaluated applications submitted for modifications from existing gasoline dispensing
facilities to analyze the potential impact on future modified permits. Over the five-year permitting
period from October 1, 2009 through October 1, 2014, SCAQMD staff processed approximately
1,200 modified permits for gasoline dispensing facilities. Out of the 1,200 modified permits, staff
conducted a detailed review of a subset of 300 permits, which were randomly chosen. This sample
size was selected to provide a 95 percent confidence level and a 5 percent margin of error in the
analysis.
Of the 300 permits for existing gasoline dispensing facilities filing for a permit for modifications
between 2009 and 2014, 267 (-89 percent) modifications were associated with no emission
increase and were exempt from Rule 1401. The rest of the permit modifications (33 of 300) were
associated with an emission increase and triggered Rule 1401. Of the 33 permit modifications that
triggered Rule 1401, 28 gasoline dispensing facilities used Tier 2 analysis and 5 gasoline
dispensing facilities used Tier 4 analysis. The approach used to analyze potential impacts to
modified permits was the same for new permitted gasoline dispensing facilities.
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For the 28 modified permits that used Tier 2 screening analysis, the estimated cancer risks for all
28 gasoline dispensing facilities remained below the Rule 1401 thresholds when using the
proposed SCAQMD Risk Assessment Procedures (Version 8.1). For the 5 modified permits that
used Tier 4 dispersion modeling, two gasoline dispensing facilities would have an increase in the
estimated health risk, but estimated health risk is < 10 in a million. Estimated health risk for the
remaining three gasoline dispensing facilities is expected to decrease. Therefore, based on the
evaluation of 300 modified permits, no impact to future modified gasoline dispensing facilities is
expected with the proposed SCAQMD Risk Assessment Procedures (Version 8.1).
Summary of Analysis on Gasoline Dispensing Facilities
Based on the detailed review of 173 new or modified gasoline dispensing facilities triggering Rule
1401 requirements from October 2009 to December 2016, the implementation of the proposed
SCAQMD Risk Assessment Procedures (Version 8.1) will result in no impact for 97 percent of
permit applications. Note that these impacts were estimated assuming the emission factor of 0.42
lbs per 1,000 gallons for Phase II refueling of ORVR-equipped vehicles, as a conservative estimate
of cancer risk. If the current emission factor of 0.32 lbs per 1,000 gallons are used, the emissions
and the associated cancer risk would be lower, resulting in fewer impacts than those presented
above.
With a 95 percent confidence level, approximately three percent of permit applicants may need to
proceed to a higher tier analysis (Tier 3: Screening Dispersion Modeling or Tier 4: Detailed Risk
Assessment), consider reducing their throughput, or new gasoline dispensing facilities could
increase the distance between emission sources and the nearest receptor. With SCAQMD
receiving, on average, about 27 permit applications annually, approximately one permit could be
affected by the proposed SCAQMD Risk Assessment Procedures (Version 8.1) per year.
Therefore, the impact of the proposed amendments on gasoline dispensing facilities is minimal.
Therefore, staff recommends removing the exemption and referencing the proposed SCAQMD
Risk Assessment Procedures (Version 8.1) for gasoline dispensing facilities.
LIST OF APPLICABLE TOXIC AIR CONTAMINANTS
Table 1 of Rule 1401 lists the toxic air contaminants that are subject to the rule and used to estimate
health risks. The list consists of the compounds that OEHHA has provided acute, chronic, or
carcinogenic health values. Periodically, OEHHA publishes new or updated health values and
subsequently SCAQMD amends Table 1 to incorporate the new or updated information. Table 1
was last updated in 2010; in the interim, a number of health values have been published by
OEHHA. Additionally, several compounds will be included on the list for clarity and consistency
with California Air Resources Board's Consolidated Table of OEHHA/ARB Approved Risk
Assessment Health Values which was last updated on February 23, 201710
New Compounds
Caprolactum (Chemical Abstracts Service Number 105-60-2) — In 2013, OEHHA developed acute
and chronic Reference Exposure Levels of 50 µg/m3 and 2.2 µg/m3 respectively. OEHHA states
that exposure to caprolactum has been found to cause upper respiratory and eye irritation in both
animals and humans; inflammation of the nasal and laryngeal epithelium in rodents; and reduced
10 Available on the internet at: littps://www.ai-b.ca.gov/toxies/healthval/contable.pd
24-40
weight of offspring for pregnant rats administered high doses orally. According to OEHHA11, the
increased eye blink frequency with eye irritation are manifestations of the same underlying event
of ocular trigeminal nerve activation. Thus, the acute reference exposure limit is based on eye
blink frequency. The acute reference exposure limit of 50 µg/m3 was established by applying a
species uncertainty factor of 10 to the No Observed Adverse Effect Level (NOAEL) of 500 µg/m3.
The chronic value of 2.2 µg/m3 was derived by the 95 percent lower confidence limit of the dose
producing a 5 percent response rate for the nasal respiratory and olfactory changes and the non -
keratinized laryngeal. tissue changes found at terminal sacrifice. An uncertainty factor of 60 was
applied because of interspecies and study length uncertainties.
The main use of caprolactum is in the polymerization process during the manufacture of Nylon -6.
Nylon -6 is a widely used type of nylon and is found in textiles, engineered plastics, and films used
in packaging and medical applications. Exposure to caprolactum may occur during the production
and recycling of Nylon -6, and offgassing from carpeting and other textiles containing Nylon -6.
Permitted use of caprolactum will occur nearly exclusively in resin manufacturing facilities. As a
Volatile Organic Compound, caprolactum emissions are already regulated in resin manufacturing
facilities by SCAQMD Rule 1141— Control of Volatile Organic Compound Emissions from Resin
Manufacturing. The provisions in that rule require that volatile organic compound emissions,
including caprolactum emissions, be reduced by 95 percent or more from blending, reaction, and
processing operations. Therefore, the addition of acute and chronic health risk values are not
expected to have any additional impacts on resin manufacturing operations as they already are
required to control caprolactum emissions.
Carbonyl sulfide (Chemical Abstracts Service Number 463-58-1) — In 2017, OEIIIIA developed
acute and chronic Reference Exposure Levels of 660 µg/m3 and 10 µg/m3 respectively12. OEHHA
found that inhalation of carbonyl sulfide results in adverse health effects in the central nervous
system. The NOAEL for carbonyl sulfide is 1,500,000 µg/m3. The time -adjusted one hour
NOAEL is 1,300,000 µg/m3. The acute reference exposure limit was determined by applying an
uncertainty factor of 2,000 to the time -adjusted one hour NOAEL resulting in an acute reference
exposure limit of 660 µg/m3. The uncertainty factor was based on limited information on acute
toxicity and there were no pharmacokinetic modeling data available. For chronic exposures, the
time -adjusted NOAEL was determined to be 130,000 µg/m3. An uncertainty factor of 6,000 was
applied resulting in a chronic reference exposure limit of 22 µg/m3. The uncertainty factor was
based on default factors for interspecies and intraspecies toxicokinetic and toxicodynamic
differences.
For industrial uses, carbonyl sulfide is emitted from some refineries as an end product of sulfur
combustion. It is also a potential grain fumigant replacing methyl bromide. In 2012, reported
emissions of carbonyl sulfide in SCAQMD was just over 15,000 pounds annually with the largest
facility reporting 7,706 pounds of annual emissions.
Refinery sources and potential fumigant sources of carbonyl sulfide are already closely controlled.
Refineries reporting carbonyl sulfide emissions already determine health risks by accounting for
" Available on the internet at: https: //o eh h a. ca, gov/media/downloads/ernr/caprolaetain2013.p df
12 Available on the internet at: https:Hoeliha.ca.aov/media!downloads/crm�/cosreIO22117.pdf
24-41
contributions from carbonyl sulfide in the Air Toxics Hot Spots Program. Additionally, sulfur
emissions are regulated as criteria pollutants necessitating the use of control equipment. The
inclusion of acute and chronic non -cancer health values for carbonyl sulfide are not expected to
require additional pollution controls as the sources of those emissions already are expected to have
pollution control.
Compounds with Added Health Risk Values
Butadiene, 1,3- (Chemical Abstracts Service Number 106-99-0) — In 2013, OEHHA developed an
acute reference exposure level of 660 µg/m3 13 At the same time, OEHHA also updated the
chronic inhalation health value to 2.0 µg/m3. In 1992, OEHHA established a cancer inhalation
unit risk value of 1.7x10-4 (µg/m3)-1. For permitted units, the cancer risk is generally orders of
magnitude greater than the acute risk. Therefore the inclusion of an acute reference exposure level
for 1,3- butadiene is not expected to have any additional impacts on permitted sources.
Methylene diphenyl diisocyanate — (Chemical Abstracts Service Number 101-68-8) — In 2016,
OEHHA developed an acute reference exposure level of 12 ug/m3 14 and updated the chronic
reference exposure level to 8.0x10-2 ug/m3. The chronic reference exposure level is more than two
magnitudes lower than the acute reference exposure level and thus the inclusion of an acute
reference exposure level is not expected to have any additional impacts on permitted sources. In
addition, a typographical error was corrected for this compound.
Toluene diisocyanates (Chemical Abstracts Service Number 26471-62-5), including toluene-2,4-
diisocyante (Chemical Abstracts Service Number 584-84-9) and toluene-2,6-diisocyantate
(Chemical Abstracts Service Number 91-08-7) — In 2016, OEHHA developed an acute reference
exposure level of 2.0 µg/m3 for the parent compound of toluene diisocyante and related compounds
toluene-2,4-diisocyante and toluene-2,6-diisocyantate15. The chronic reference exposure level was
also updated at the same time to 8x10-3 µg/m3. However, the cancer inhalation unit risk,
established in 1999, is 1.1x10-5 (µg/m3)-1 resulting in a cancer risk that is generally orders of
magnitude greater than the acute risk. For permitted units, the inclusion of an acute reference
exposure level for toluene diisocyantes is not expected to have any additional impacts.
Compounds Added for Clarification and Consistency
In two cases, a parent compound is listed in Table 1 of Rule 1401 while some associated
compounds are not. To clarify the applicability of the compounds and to make Table 1 more
consistent with CARB's Consolidated Table of OEHHA/ARB Approved Risk Assessment Health
Values (February 23, 2017), the following related compounds in Table 6 below will be added to
Table 1 of Rule 1401:
13 Available on the internet at: https://oehha.ca.gov/media/downloads/crnr/0-/2613bentcrel.pddf
14 Available on the internet at: https://oehha.ca.aov/media/downIoads/air/report-hot-spots/finalmdireImarch2016.pdf
is Available on the internet at: https:Hoehlia.ca.,ov/media/downloads/air/report-hot-spots/finaltdirelniarch20'l6.pddf
24-42
Table 6: Related Compounds Added for Clarification and Consistency
Barium chromate
10294-40-3
Chromium (hexavalent)-
hexavalent)Calcium
Calciumchromate
13765-19-0
Chromium (hexavalent)
Chromic trioxide
1333-82-0
Chromium (hexavalent)
Sodium dichromate
10588-01-9
Chromium (hexavalent)
Strontium chromate
7789-06-2
Chromium (hexavalent)
Zinc chromate
13530-65-9
Chromium (hexavalent)
Hexachlorocyclohexane, alpha
319-85-6
Hexachlorocyclohexanes (mixed or
technical grade)
Hexachlorocyclohexane, beta
319-85-7
Hexachlorocyclohexanes (mixed or
technical grade)
Similarly, in two other cases, a related compound is listed in Table 1 while the parent compound
is not. The following parent compounds will be added to Table 1 of Rule 1401 as shown in Table
7 below.
Table 7: Parent Compounds Added for Clarification and Consistency
For both the newly added parent and related compounds, the effective date of rule applicability
will be the same as the already listed compound.
Finally, a typographical error was corrected as the same compound, vinylidene chloride and
dichloroethylene, 1,1- (Chemical Abstracts Service Number 75-35-4), is listed twice. To avoid
confusion, the compound will remain listed twice but the dichloroethylene, 1,1- will refer back to
vinylidene chloride.
AFFECTED INDUSTRIES
Implementation of PAR 1401 is expected to potentially increase the estimated cancer risks for
spray booths and gasoline dispensing facilities. SCAQNM staff conducted an analysis to better
understand the number of sources that could be potential affected by the proposal. Staff estimates
two spray booth permits annually could require higher level of air pollution controls. The expected
additional air pollution control would be the replacement of NEPA filters with ULPA filters. For
gasoline dispensing facilities, one permit applications annually will have a lower permitted
throughput, consider increasing their distance of emission sources to the nearest residential
receptor, or proceed to a Tier 3 or Tier 4 analysis requiring dispersion modeling. Finally, five
refineries will see a negligible increase in cancer risk because of the addition of carbonyl sulfide
to the Rule 1401 Toxic Air Contaminant list.
SOCIOECONOMIC ASSESSMENT
PAR 1401 would require the use of the proposed SCAQMD Risk Assessment Procedures (Version
8. 1), also referred to as Procedures, when determining health risks for all new and modified
permitted equipment and processes at spray booths and gasoline dispensing facilities. The updates
to the Procedures could potentially increase the calculated cancer risk for emission sources at the
affected facilities. Based on staff's analysis of SCAQMD permits issued from October 1, 2009
through October 1, 2014, two spray booths and one gasoline dispensing facility per year could
potentially incur costs to comply with PAR 140116. Spray booths belong to various sectors of the
economy such as manufacturing, wholesale, retail, services, and the affected gasoline dispensing
facilities belong to the sector of retail services. As spray booths and gasoline dispensing facilities
tend to be small businesses, the potentially affected facilities by the proposed amendments are also
likely to be small businesses.
For the potentially affected spray booths with new or modified permits, an average of two facilities
per year are expected to need to install ULPA filters in lieu of HEPA filters to comply with PAR
1401. The unit cost of ULPA filters is expected to be very similar to the unit cost of HEPA filters.
However, ULPA filters require the use of higher horsepower blowers. For a typical size of spray
booth, a 15 HP blower will be needed for ULPA filters as opposed to a 10 HP blower for NEPA
filters. A 15 HP blower is more expensive than a 10 HP blower, and it also uses more electricity
which would result in a higher operation cost. The incremental cost of a 15 HP blower over a 10
HP blower is estimated at $750 ($4,250 for a 15 HP blower vs $3,500 for a 10 HP blower). The
incremental operating cost related to additional electrical usage is estimated at $595 annually
($0.13/kWh X 2.2 IM X 8 hours/day X 5 days/week X 52 weeks/year).17 Based on a typical
equipment life of five years, the present value of the total incremental costs of purchasing and
operating a 15 HP blower is estimated to be up to $3,725 per facility [$750 + $595 X 51, or $7,450
for a total of two potentially affected spray booths. 18
For the potentially affected gasoline dispensing facilities with new or modified permits, ari average
of one facility per year is expected to proceed to the more complicated Tier 3 or Tier 4 HRA unless
the facility can lower its permitted throughput or increase the distance between the emission
sources to the nearest receptor. For the purpose of the socioeconomic impact assessment, it is
assumed that the affected facility would proceed to a Tier 4 HRA, which would require dispersion
modeling to predict the atmospheric concentrations of gaseous and particulate pollutants using
site-specific input parameters. Based on a vendor's price quote, the annual cost of dispersion
modeling is estimated at $15,000 per gasoline dispensing facility.
Therefore, the overall compliance cost is estimated at $22,450 ($7,450+$15,000) per year based
on the assumption that, each year after PAR 1401 adoption, there will be two spray booths and one
gasoline dispensing facility applying for new or modified permits that will need to fulfill additional
16 For new gasoline dispensing facilities, staff analyzed permits up to December 2016.
17 $0.13/kWh represents the average commercial electricity rate in the City of Los Angeles (see
http://www.eIectricitylocal.com/states/califolnia/los-angeIes/). Additionally. the blower is assumed to be operated at
the 50 -percent capacity to reach the typical five-year equipment life.
18 The present value of $3,725 per spray booth is derived by assuming a zero discount rate. The amount would decrease
if a greater discount rate is used. Notice this cost may recur every five years if ULPA filters would continue to be
required for these facilities and the differences in the capital and operation costs would continue to remain the same
between a 15 HP and a 10 HP blower.
24-44
requirements to comply with PAR 1401. It has been a standard socioeconomic practice that, when
the annual compliance cost is less than one million current U.S. dollars, the Regional Economic
Models Inc. (REMI)'s Policy Insight Plus Model is not used to simulate jobs and macroeconomic
impacts. This is because the resultant impacts would be diminutive relative to the baseline regional
economy.
CALIFORNIA ENVIRONMENTAL QUALITY ACT ANALYSIS
Pursuant to the California Environmental Quality Act (CEQA) and SCAQMD Rule 110, the
SCAQMD, as lead agency for the proposed project, has reviewed the proposed amendments to
Rule 1401 pursuant to: 1) CEQA Guidelines § 15002(k) — General Concepts, the three-step
process for deciding which document to prepare for a project subject to CEQA; and 2) CEQA
Guidelines § 15061 — Review for Exemption, procedures for determining if a project is exempt
from CEQA. SCAQMD staff has determined that it can be seen with certainty that there is no
possibility that the proposed amendments to Rule 1401 may have a significant adverse effect on
the environment. Therefore, PAR 1401 is considered to be exempt from CEQA pursuant to CEQA
Guidelines § 15061(b)(3) — Activities Covered by General Rule. A Notice of Exemption will be
prepared pursuant to CEQA Guidelines § 15062 - Notice of Exemption. If the project is approved,
the Notice of Exemption will be filed with the county clerks of Los Angeles, Orange, Riverside
and San Bernardino counties.
DRAFT FINDINGS UNDER CALIFORNIA HEALTH AND SAFETY CODE
SECTION 40727
Requirements to Make Findings
California Health and Safety Code Section 40727 requires that prior to adopting, amending or
repealing a rule or regulation, the SCAQMD Governing Board shall make findings of necessity,
authority, clarity, consistency, non -duplication, and reference based on relevant information
presented at the public hearing and in the staff report.
Necessity
PAR 1401 is needed to update rule language relating to risk assessment calculations such that they
are consistent with those specified in the state OEHHA Risk Assessment Guidelines adopted on
March 6, 2015.
Authority
The SCAQMD Governing Board has authority to adopt amendments to Rule 1401 pursuant to the
California Health and Safety Code Sections 39002, 39650 et. Seq., 40000, 40001, 40440, 40441,
40702, 40725 through 40728, 41508, 41700, 41706, 44360 through 44366, and 44390 through
44394.
Clarity
PAR 1401 is written or displayed so that its meaning can be easily understood by the persons
directly affected by it.
Consistency
PAR 1401 is in harmony with and not in conflict with or contradictory to, existing statutes, court
decisions or state or federal regulations.
24-45
Non -Duplication
PAR 1401 will not impose the same requirements as any existing state or federal regulations. The
proposed amended rule is necessary and proper to execute the powers and duties granted to, and
imposed upon, the SCAQMD.
Reference
By adopting PAR 1401, the SCAQMD Governing Board will be implementing, interpreting or
making specific the provisions of the California Health and Safety Code Sections 39666 (District
new source review rules for toxics), 41700 (prohibited discharges), and 44360 through 44366 (Risk
Assessment).
Rule Adoption Relative to Cost-effectiveness
On October 14, 1994, the Governing Board adopted a resolution that requires staff to address
whether rules being proposed for adoption are considered in the order of cost-effectiveness. The
2016 Air Quality Management Plan (AQMP) ranked, in the order of cost-effectiveness, all of the
control measures for which costs were quantified. It is generally recommended that the most cost-
effective actions be taken first. However, PAR 1401 is not a control measure that was included in
the 2016 AQMP and was not ranked relative to other criteria pollutant control measures in the
2016 AQMP.
Incremental Cost-effectiveness
Health and Safety Code Section 40920.6 requires an incremental cost effectiveness analysis for
Best Available Retrofit Control Technology (BARCT) rules or emission reduction strategies when
there is more than one control option which would achieve the emission reduction objective of the
proposed amendments, relative to ozone, CO, SOx, Nox, and their precursors. Since PAR 1401
applies to toxic air contaminants, the incremental cost effectiveness analysis requirement does not
apply.
COMPARATIVE ANALYSIS
Health and Safety Code section 40727.2 requires a comparative analysis of the proposed amended
rule with any Federal or District rules and regulations applicable to the same source. See Table 8
below.
24-46
Table 8: Comparative Analysis of PAR 1401 with Rules 212, 1401.1, 1402, and Federal
Regulations
Rule Element
PAR 1401
Rule 212
Rule 1401.1
Rule 1402
Equivalent
Federal
Re ulation
Applicability
New,
New or
New or
Existing
None
relocated or
modified
relocated
facilities
modified
permit unit
permit unit
subject to Air
permit unit
Toxics "Hot
Spots"
Information
and
Assessment
Act of 1987
and facilities
with total
facility
emissions
exceeding any
significant or
action risk
level
Requirements
Limits
Provide
Limits cancer
Submittal of
None
maximum
public
risk and
health risk
individual
notice to all
chronic and
assessment for
cancer risk,
nearby
acute hazards
total facility
cancer burden
addresses
near schools
emissions when
and chronic
projects that
notified.
and acute
are located
Implement risk
hazards
within 1,000
reduction
feet of a
measures if
school,
facility -wide
increase risk
risk is greater
or nuisance,
than or equal to
or increase
action risk
criteria
level
pollutants
above
specified
thresholds
Reporting
None
Verification
None
Progress
None
that public
reports and
notice has
updates to risk
been
reduction plans
distributed
Monitoring
None
None
None
None
None
Recordkeeping
None
None
None
None
None
24-47
Appendix A — U.S. EPA Guidance on Removing Stage II Gasoline Refueling
Vapor Recovery Programs from State Implementation Plan
On a federal level, the control efficiency of Stage II is in the range of 60- 75 percent, much lower
than the California Phase II program (95 percent). In addition, in areas where certain types of
vacuum -assist Stage II control systems are used, the limited compatibility between ORVR and
some configurations of this Stage II hardware may result in an area -wide emissions disbenefit.
U.S. EPA's regulation stated that with the widespread use of the ORVR-equipped vehicles, Stage
II programs have become largely redundant control systems with minimal reduction benefits
beyond the ORVR system. SCAQMD and CARB have commented that Phase II EVR is still
needed as discussed in more detail under their comment letters 19 submitted in response to U.S.
EPA's proposed rule titled "Widespread Use for Onboard Refueling Vapor Recovery and Stage II
Waiver." U.S. EPA's guidance does, however provide additional insight regarding the application
of emission reductions from Stage II control systems for vehicles equipped with ORVR further
demonstrating that the control efficiency of the ORVR and/or the Stage II systems are only applied
once to the respective gasoline throughput (the same control efficiency was applied to both the
throughput of Stage II and non-ORVR vehicles.
The U.S. EPA Guidance document provides two equations to calculate impacts on the refueling
emission inventory whereas the results could be used by States to support SIP actions (Section
3.3). Equation 1 determines the overall stage II-ORVR increment, which identifies the annual area -
wide emission control gain from Stage II installations as ORVR technology phases in, assuming
both have the same efficiency. It also indicates the emission reduction potential loss (in year i)
from removing Stage II. Equation 1 is shown below:
/ Equation 1
increment1 = (Qsj[)(1'QOR-,,p,)(ilj,,su) - (Qsjj,)(CFj)
The first part of the equation identifies the overall Stage II-ORVR increment. The second part of
the equation accounts the for vacuum -assist compatibility factor, which is not applicable in
California because California's Phase II EVR system requires compatibility with ORVR. Equation
1 estimates the incremental emission control gain with the widespread use of ORVR vehicles by
accounting for (1) fraction of gasoline throughput covered by Stage II vapor recovery system
(Qsli), the fraction of gasoline dispensed to non-ORVR vehicles (1-QoRvRi) and the in -use control
efficiency of the stage I1 vapor recovery system (ili„ sa)
Equation 2 determines the delta between the Stage II efficiency and the ORVR efficiency with
both technologies in place. It considers the greater efficiency of ORVR relative to non-ORVR
vehicles refueling at Stage II -equipped gasoline dispensing facilities. Equation 2 is shown below:
19 Available on the internet at
http s://www.regulations. gov/docketB rowser?ipp=50 &so=DE S C&sb=postedDate&po=0 &dct=P S &D=EPA-
HQ-OAR-2010-1076
24-48
Equation 2 > rrr11
deltai = (QsIF)(ijiusiI) - (Qsllva)(CFi) - (`�CORVP.i)(1IOR-,'R)
As demonstration in the two equations above, the control efficiency of the ORVR and / or the
Stage II systems are only applied once to the respective gasoline throughput (the same control
efficiency was applied to both the throughput of Stage II and non-ORVR vehicles in equation 1).
If the two control equipment were to work in series, the control efficiency of the two would have
been multiplied together, as the way it was determined by CARB:
ORVR, Phase It EVR = (non-ORVR UEF)*(1 - ORVR CE)*(1 - Ph II EVR CE)
= (8.4 lbs/kgal)*(1 - 0.95)*(1 - 0.95) = 0.021 lbs/kgal
Thus, SCAQMD staff's interpretation that the ORVR and Phase II vapor recovery system may not
work in series is consistent with the methodology used by U.S. EPA to determine the impacts of
removing the Stage II program.
24-49
Appendix B — Comments and Responses
California Independent Oil Marketers Association
3935 North Freeway Blvd, Suite 240
Sacramento, CA 95834-1955
916.646.5,999
July 19, 2017
Susan Nakamura Via email at: snakamura@aclmd.gov,
Assistant Deputy Executhle Officer
South Coast Air Quality Management Distnct
21865 Copley Drive
Diamond Bar, CA 91765
Re: Proposed A mended Rule 14,01- New Source Review of Tcxic Air Contaminants
Dear NT, s. Nakamura:.
These comments are presented on behalf of CIGMA, a part of the California Small Business
Alliance, members that own and operate facilities that are affected by Proposed Amended lute
1401- New Source Review of Toxic AirContaminants.
The California Independent Oil Marketers Association (CIGMA) represents about 300members,
including nearly 9D% of all, the independent petroleum marketers in the state and aboutone
quarter of the state's 10,00D serlce stations. Our members provide services to local
governments, law enforcement, city and county fire departments, ambulances/emergency
vehicles, school dkMict bus fleets, construction firms, mannas, public and privatetransit
companies, hospital emergency generators, trucking fleets, independent fuel retailers (small
chains and mom-and-pop gas stations) and California agriculture, among others.
The District is proposing to make several changes to its evaivation procedures for new and
modified gasoline dispensing facilities fGDFs) and has not disclosed key details critical to the
rule deweloprncnt, which is proceeding on a severely compressed schedule with limited public
input. CIONIA's major concerns regarding Proposed Amended Rule 1401 are as follows:
The Proposed Amended Rule 1401 rule development schedule has been aggressively
compressed, with technical documents not being provided to stakeholders prior to the set
hearing date.
The first working group meeting for Proposed Amended Rule 1401 was held on June 1, 2017; 1-1
draft rule language and the Draft Staff Report was released on June 16, 2017. Stakeholders
were also notified on June 16 of the dates of the second' working group meeting and public
workshop, scheduled for June 29 and July 12 respectively. Technical documents were f
24-50
requested by stakeholders at the first working group meeting and promised by Staff to be
available at the second working group meeting.
The second working group meeting was rescheduled for July 6, one day prior to the set hearing
scheduled forJuly 7. No technical documentation was provided by Staff at the second working
group meeting, Staff stated that the gasoline station appendix would be available by rald-July
and the Proposed Risk Assessment Procedures Version 8.1 would be available byAugust 2. A
third working group meeting was scheduled for July 20 at the request of stakeholders due to
the lack of available technical documentation to evaluate the proposed changes to Rule 1401.
The gasoline station appendix (Attachment N) was available via hard copy at the public
workshop on, July 12. Attachment N and its methodology (Appendix X) were emailed to the
Proposed Amended Rule 1401 working group list on the night of July 15. Neither document has
been posted online to the Proposed Rules page of the SCAQMD website. Tice Proposed'! Risk
Assessment Procedures (Version 8.1) will not be released until August, when many members of
Staff will be unavailable for questions or comment.
Staff is presenting the proposed rule one day after the third working group on July 21. The
public hearing for Proposed Amended Rule 1401 is scheduled for September 1, 2017. With
much of the technical documentation supporting the proposed changes in the rule being
released within the last week, or not yet released, such a short timetable has not allowed for a
robust public rulemaking process with proper stake holder input.
SCAQMD plans to increase the emission factorfor refueling activities at GDFs to the level
identified try the California Air Resources Board (GARB) for vehicles not equipped with onboard'
refueling vapor recovery JORVRI systems.
Staff is planning on increasing its emission factorfor refueling activities at GI)Fs, and'diffening
from GARB and the emissions factor SCAMAD used to develop its own emissions inventoryfor.
'
the AQPA P'. The mao rity of vehirlf-- are equipped with ORVR, and for ORVR vehicles (ARB
identified an emission factor twenty tim es lower than non -0 RVR vehicles. The District n eedsto
provide more technical information for its own proposed emission factor, and identify why it
appears to be disregarding g 0 RVR entirely. Stakeholders are not able to determine the analysis
lysis
behind Staff's increase in the emissions factor and divergence from CARB's determination for
GRVR vehicles without access to the Proposed Risk Assessment Procedures (Version 8-1), which
will not be available until August
The Governing Board adoption hearing for Proposed Adopted Rule 1401 should,. Id be delayed
from the September 1, 2017 date,
Conclusion ' 1-3
Due to the lack of availability of technical documents to stakeholders, the constricted
rulemaking schedule pushed up againstthe SCAQMD August summer recess, and the need for
MMI
continued technical analysis due to the implications of the proposed changes, the date of the
Governing Board adoption hearing for Proposed Adopted Rule 1401 should bedelayed.
Stakeholders have not had the proper opportunity to have access to key technical documents
critical to proposed changes to the emission factor for refueling activities at GDFs, and will not 1-3
have the opportunity to make comments in a timely fashion due to the rulemaking and staff
schedule. The hearing should be delayed to ensure the proper public rulemaking process takes
place and all analysis is completed in a thoughtful., transparentmanner. f
Please contact Samuel Bayless at baylers@cioma.com or (916) 646-5999 with any questions.
Sincerely,
Samuel Bayless
Regulatory Issues Specialist
California Independent Oil Marketers Association
CC:
Wayne Nastri, SCAQMD Executive Officer
Philip Fine, Ph.D, SCAQN-11) Deputy Executive Officer
Ben Benoit, Mayor Pro Tem, City of Wildomar
Joseph Lyou, Ph.D, Governor's Appointee /SCACLNAD Governing Board
Judith Mitchell, Councilmember, City of Rolling Hill's Estates
Shawn Nelson, Supervisor, fourth Distria/County of Orange
Janice Rutherford, Supervisor, Second District/County of San Bernardino
Sheila Kuehl, Supervisor, Third District/County of Los Angeles
Ruthanne Taylor Berger, Board Assistant to Ben Benoit
Mark AbramovAtz, Board Assistant to Dr. Joseph, Lyou
Marisa Perez, Board Assistant to Judith Mitchel[
Denis Bilodeau, Board Assistant to Shawn Nelson
Mark Taylor, Chief of Staff to Janice Rutherford
Andrew Silva, Board Assistant to Janice Rutherford
Diane Moss, Board Assistant to Sheila Kuehl
24-52
Response to Comment 1-1
In the first working group meeting, staff presented the proposed emission factors for gasoline
dispensing facilities, and agreed to invite a subject matter expert from Engineering & Permitting
to the next working group to provide a technical explanation.
Draft Proposed Amended Rule 1401 and the Preliminary Draft Staff Report were released on June
16, more than 75 days before the public hearing.
In the second working group meeting, staff presented more background information and the
technical basis of the proposed emission factors link), and provided clarification and justification
for the proposal. To address the concerns on the potential impacts on gasoline dispensing facilities,
both the Preliminary Draft of Appendix X - Methodology Used to Develop Tier 2 Screening Tables
for Gasoline Transfer and Dispensing Facilities and the corresponding Attachment N screening
tables from proposed SCAQMD Risk Assessment Procedures (Version 8.1) were released on July
15. A third working group meeting was held to walls the stakeholders through and answer any
questions on these two documents.
On July 21, the proposed amendments to Rule 1401 and the associated impacts were presented to
the Stationary Source Committee. Staff highlighted the key issues on the proposed emission factors
of gasoline dispensing facilities and the rule development schedule. Both issues were thoroughly
discussed among Committee members, staff, and stakeholders.
A Draft Staff Report, including additional information on the technologies of the ORVR and Phase
II vapor recovery system, as well as the rationale behind using the current SCAQMD emission
factor for refueling (0.32 lbs per 1,000 gallons) has been released on August 2. Staff is available
to hold another working group meeting in August to address any questions or concerns that may
arise.
In brief, the proposed rule language, the Preliminary Draft Staff Report, Draft Staff Report (which
also includes the Socioeconomic Analysis) have been released following the rule development
schedule, and additional technical justification has been provided to stakeholders in a timely
manner upon request.
Response to Comment 1-2
As discussed in Response to Comment 1-1, additional background information and technical
justification was provided in the second working group meeting on July 6. The sections relevant
to gasoline dispensing facilities from Proposed Risk Assessment Procedures Version 8.1 were
released on July 15 and a working group meeting was held on July 20 to address questions and
concerns on the documents.
As discussed at the Working Group meetings, based on the available test data from CARB and
EPA, SCAQMD staff concluded that the Phase II vapor recovery system and ORVR systems
would each achieve a 95% control efficiency. However, there is no empirical evidence to support
the assumption that all the vapors escaping from the ORVR system are directed to the.fillpipe and
can be captured by the Phase II EVR system. For more information, please refer to Response to
Comment 2-2.
24-53
On the emission factor used for the refueling in gasoline dispensing facilities in the 2016 AQMP,
please refer to Comment 2-6.
Response to Comment 1-3
PAR 1401 has followed a typical rule development 'schedule and has met the requirements of
SCAQMD's public process for rulemaking. Upon request, additional technical justification has
also been provided to stakeholders in a timely manner. Staff is available for follow up meetings to
answer questions or provide clarifications before the Public Hearing.
24-54
I�
Pillst,.xy %Vonthrop Shaw Rmin LLP'
725 So Ah Figuema Street, Sahe 2B00 I Los Angeles, CA 90017-5405 I tel 213,486.711;O I fax 213.629.1033
Michael S. hie-Donough
tel: 213.463.7 555
ni.ich.iel.mcdonough,,ea;piJisburylaw.com
July 25, 2017
Ms. Y—darn Cheung
Planning, Ride Development and Area Sources
South Coast Air Quality Management District
21865 Copley Drive
Diamond Bar, CA 91765
Email: k-cheung7.0'!qgrnd,go7,;,
Re: Costco'"rholesale CoiVoration Comments on SC.ALQ-NED Proposed
Amended Ride 1401
Dear Ms. Cheung:
Costco Wholesale Corporation appreciates this opporftuUty to provide comments on
the South Coast Air Quality Management District's Proposed Amended Rule (NLR)
1401—New Source Review of Toxic Air Contaminants. As you know., for years
Costco has stood at the forefront of emissions control efforts concerning California
gasoline dispensing facilities (GDFs)- Costco his worked closely with the District
and the California Air Resources Board (ARB) over many years to develop and test
cutting-edge in -station diagnostic JSD) technologies designed to automatically detect
,vapor recovery system failures and avoid volatile organic conipotuid (VOC)
emissions through early detection and repair. In many cases, VOC emissions
reduction technologies tested and adopted by Costco have gone well beyondwhat the
regulations require- This is because Costco has made a commitment to conduct all of
its , operations in an environmentally responsible and sustainable manner, reco . ing
2-1
that in order for Costco to thrive. our world and shared environment must also thrive.
IV, e believe that sound environmental policy requires use of the latest and best
scientific data available. Accordingly, we commend the District for proposing
aniendnients to District Rule 1401 that strive to incorporate the most up-to-date
informationavailable regarding the emissions perfornmace of today's GDFs. As you
u
know. advances in enhanced vapor recovery (E R) technology in the past few
decades have literally changed the face of GDF regulation. Onboard refueling vapor
recovery (ORVF�) technology, which results in capture of_g reater than 95% of all
organic vapors fronia passenger car gas tank- during refueling, is required to be
wyowpillsburyiaw.cvrn
4312-8492-7052.vl
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Ms. Malar Cheung
7uly25_2017
Page 2
installed on new passenger cars and is now present on the vast majority of cars on
California's roads. In addition, Phase Iand 11 EVR technologies installed in gasoline
underground storage tanks and gasoline punT nozzles, respectively, provide
additional control of gasoline vapors displaced from DST's and vehicle gas tanks
during refilling, further ensuring an extreniely low VOC emissions profile at today's
GDFs. Nfarket penetration of these technologies has risen draniatically in just the last
decade alone, meaning that estimates of GDF emissions today are now., thankfully, far
lov;er than estimates from ten years ago_
Thus,. Costco was very pleased to work with the District and ARB over that past
decade not only to implement EVRat its California GDFs, but also to gather the, data
necessary to update the stateivide VOC and toxics enfissions factors applicable to
GDFs. Prior GDF emission factors were adopted in 1999,and did not account for jj
technological advances in Phase 1, Phase II and OR'VR technologies implemented
o,wr the next 15 yTars. For that reason, ARB invited several air districts and other
stakeholders to collaborate in a multi-year study of GDF emissions using clurent
technologies- As you knowon December 23, 2013 ARB released its "Revised
Emission Factors for Gasoline Marketing Operations at California Gasoline
Dispensing Facilities' (ARB 2013 GDF Fa c tors) 1 updating emissions factors for
Phase I transfers and Phase H refue&g, and adding new emissions sub -categories for
Phase H refueling of ORX-R-equipped vehicles and gasoline dispensing hose
permeation- We understand the District participated closely in this process.
In, relevant part, PAR 1401 seeks to update the District's new source review rule, for
toric ealissions sources by requiring the use of proposed S C.A.QNf D Risk Assessment
Procedures Version S_1 in risk assessments fo r all new and modified spray booths and
GDFs. This XTersion, S.1 also -proposes to incorporate all of ARB's updates to GDF
speciation profiles and emissions factors except for one: the factor for refueling of
ORX'Ik7equipped vehicles by Phase R -equipped pumps. ARB has determined that
refueling of non-OR�R-eqiiippedtrehicles by Phase H nozzles results in V OC
emissions of 0.422 pound,'1,000 gallons of gasoline throughput, and that refueling of 2-2
ORITR-equipped vehicles by Phase H nozzles results in a lower emissions profile of
0.021 poim&1,000 gallons gasoline throughput. Here, the District's Version S.1 of
the Risk Assessment Procedures proposes in emission factor of 0.42 Poundq'000
gallons gasoline throughput for refueling of ORNa vehicles gLnon-ORNRvehicles;
at a Phase H nozzle. This Nvould assume that addition of ORVR control provides no
emissions benefit Whatsoever in reducing refueling emissions at a Phase H pump,
The ARB 2013 GDF Factor-, document and its attacbment, are available on ARB', website at
wyrw.pil ISt'.IrYia'.vx0"n
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Ms. Kalam Cheung
July 25, 2017
Page 3
This would flatly cantradict.ARB's studied finding in the 2013 A -RB GDF Factors
document- As a result, of its multi--
year analysis and study of GDF IVOC emissions,
ARB concluded that, while ORVRs�ystems avefag)E! 95% capture efficiency of gas
tank emissions during refueling (i -e- capture of vapors in the onboard carbon canister
for routing to the engine), the additional use of a Phase 11 nozzle (y;hich IIS its own
95% control efficieneNy) ivill prevent escape of most of these iremaininguncaptared
vapors into the atmosphere. See ARB 2013 GDF Factors, Attachment 1. p. 7 (95%
control efficiency of Phase H prairides additional benefit to 95% control ofORNIR). 2 -
Empirical evidence of the sig nificiat compound effect of multiple vapor controls was
established in a 2008,ARB empirical study of en isssions from OMIR-equipped
vehicles during refueling. ARB'sstudy found that the addition of Phase H controls to
ORVR control provided roughly an order of magnitude nuprovement in emission
reduction, versus ORVR control without Pliase IL See California Air Resources
Board. Ifeasureinent of Gasol'ine Maypor Dnissions T�-qni 11'ehicles Equipped with On
Board Tiapor Rwcoveq, p. 15, Table 7 (July 24- 2009). The, table reproduced below
from FRB's 2009 study sumniirized the data comparing the two emissions scenarios:
(see- nage_..)
The 200SARB study can be found on r' 's vrebsite at
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Ms. Kalam Cheung
July 25. 2017
Page 4
Table 7
Emissions data for ORVR Vehicles from ARB tests at gasoline dispensing
facilities and /rein EPA/Manofarturer SHED tests
As ARB's data shot.•. N70C fillpipe emissions daring refueling of CaRFG Winter Fuel
at a non -Phase II equipped nozzle were estimated to be roughly 0.1 pound11,000
gallons gasoline throughput (data line 1), while VOC filipipe emissions during
refueling of CaUG Winter Fuel at a Phase II -equipped nozzle were estimated at 0.01
pound/1,000 gallons gasoline throughput (data line 3). Thus, according to ARB, the -'-?
addition of Phase II control when refueling an ORVR-equipped vehicle improved the
overall VOC capture efficiency by 10 times over use of ORN'R alone. This sq uely
contradicts the District's use of the santee emissions factor (0.42) for ORVR. _ Phase II
and for ORNTR alone.
In September 2011, ARB again concluded in a 111ite Paper responding to EPA's
proposed " widespread use" finding and Stage II waiver that the use of ORVR
toeether with Phase II control significwtly reduced refueling emissions versus use of ,
ORVR alone. ARB noted that emissions of hydrocarbon'VOCs when refueling a -
non-ORVR vehicle from a Phase II pump were nearly 40 times higher (0.38
pound11,000 gallons gasoline dispensed) than when ORVR control is added (0.01
wvrw.P it lS&Fylxx.cam
4SIM492.7052xI
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Emissions, lbs per IWO Gallons dislpensed
CaRFG3 Sunrn r Ft i
Fedetr Til
CaRFCa3 Wailer
Emission Measmements
69RVP
Froc ileFuel; 9 RVP
Fu -0, I 19 F
ARB Test Procedure 201,2 at Gasoline dispensino facilities
Filpipe, no Phase 0, mean .
0.043± 008
0 094 ± 0.18
d (Wiaaton(This stud
Average odmAef reaftng; ms,
&or V'-Vluc s In to sway, A -
13,400
14,100
2007 model years
Rippe,'math Phase i EVR
Clot
tAv of t*o ARB studk�s.f
EM—Wed redtxbon of H pe
ealssk)mTcv ORVR veNde w4h
tl c rd (vaster tuet, RVP
0 0
not Mdied'
EPA'hlanufactrrers ORVR vehicle emissions measurement according to the Federal Test
Procedure
FTl ' e aW onboard ca6stef
o ss' + std deviallon (Average
0 26 t 1.15
W d ng eve( -W
19.100
lAvefaae odxmter read n les
Nhmitw of VOICNes to qV 0 2 gr ORVR standara = 17, of 5.3% of V Ncl tested
As ARB's data shot.•. N70C fillpipe emissions daring refueling of CaRFG Winter Fuel
at a non -Phase II equipped nozzle were estimated to be roughly 0.1 pound11,000
gallons gasoline throughput (data line 1), while VOC filipipe emissions during
refueling of CaUG Winter Fuel at a Phase II -equipped nozzle were estimated at 0.01
pound/1,000 gallons gasoline throughput (data line 3). Thus, according to ARB, the -'-?
addition of Phase II control when refueling an ORVR-equipped vehicle improved the
overall VOC capture efficiency by 10 times over use of ORN'R alone. This sq uely
contradicts the District's use of the santee emissions factor (0.42) for ORVR. _ Phase II
and for ORNTR alone.
In September 2011, ARB again concluded in a 111ite Paper responding to EPA's
proposed " widespread use" finding and Stage II waiver that the use of ORVR
toeether with Phase II control significwtly reduced refueling emissions versus use of ,
ORVR alone. ARB noted that emissions of hydrocarbon'VOCs when refueling a -
non-ORVR vehicle from a Phase II pump were nearly 40 times higher (0.38
pound11,000 gallons gasoline dispensed) than when ORVR control is added (0.01
wvrw.P it lS&Fylxx.cam
4SIM492.7052xI
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Ms. Kalam Cheung
July 25, 2017
Page 5
pound/1,000 gallons gasoline dispensed), as shown in the below excerpt from the
Mute Paper:
Table 2
Emission Faclors for Velilcka Fuehrap Opefotions
See ARB U ite Paper, Prelinrinan, Analysis of U.S. EP4's Proposed Rule on
Onboard Refueling Mapor Recoveq 175despread Use Determination and Califorwta's
Enllmtcerl V npor Recover tj Rer7lrirernents, p. 6 (Sept. S, 2011).' In its letter to EPA
accompanying the White Paper, ARB argued against the removal of Phase H EVR}
_.s
requirements in California despite EPA's finding of ORVR "widespread use," noting
that "(ORVR) and Stage H (Phase 11) are both designed to control the vehicle
refueling emissions and both are effective." .See Letter from James Goldstene to EPA
Air and Radiation Docket and Infonuation Center, p. 1 (Sept. S, 2011).'
To date, District staff have provided no empirical data or evidence to substantiate
their rejection of the ARB 2013 GDF emission factor for ORVR/Phase II refueling,
nor has the District provided evidence or data to refute ARB's empirical analyses. In
the public work -shops on this mile, District staff have repeatedly asserted that they are
"confident" that the ARB emissions factor is based on "double counting" of emissions
controls. Staff further assert that their conclusion is based on an "engineering
disagreement" with ARB. But District staff have not presented any empirical ?-t
emissions data to support these assertions, nor has ARB provided any public response
to date as to the validity of District staff's claims.
We believe it is problematic from a policy perspective for the District to adopt an
emission factor in direct contravention of an emissions factor set by ARB based on
empirical evidence and years of analysis, particularly where the District is unable to
The white Paper and accompanying ARB letter to EPA can be found on ARB'-- website at
1:" r-'w—v r,. ib. ca.eov,vavoc.lcab°t f4spon °:
Ms. Kalam Cheung
July 25,2017
Page 6
produce data or evidence of its own to justifV the rejection of ARB's findings, IVhen
the District disagrees with ARB over engineering conclusions that are amenable to
ear determination — especially as to emissions factors that should have uniform
statewide applicabilihy —xve believe it is incumbent on District stff to work out their
differences with ARB and ulthnately defer to evidence and data.
We also believe that it is potentially dangerous ground for District stiff to take a
position ,suggesting that Phase H controls have zero benefit to controlling refueling
emissions versus use of ORNTRalone- This position would have, farther -retching
consequences for the District than, just in this ruleni*ing. As the, District knolxs,
California opposed EPA's -x4idespread use" determination Indeed, in the 2016 Air
Qtiahty Nfan-agement Plan, the District has already taken Basinivide credit for
emissions reductions from GDFs by applying the .suite of ARB 2013 GDF Factors
(seR 2016 AQNIP, Appen&x III, pp- IIIA -15 to 111-1-16),1 putting the District in the
position of potentially contradicting its own AQI%.IP by only selectively adopting
,same but not all of the ARB 2013 GDF Factors.
As ive have explained in the public, ivorkshops and working groups on PAR 1101,
Costco 1xholeheartedly agrees with the District's adoption of the ARB 2013 GDF
Factors, but simply belie tes that the available data from ARB ,supports adoption of a
of the ARB factors, including the ORVRThase H factor. Costco agrees with District
Staff's position that the GDF emissions factors themsely es do not requireactail
rut , so we believe this one remaining oversight can and should be remedied
by District Staff— if not in conjunction vdth this rulemaking, then immediately
fOUoxvkg it.
Everyone — the District, regulated entities, and the public — has a strong interest in
ensuring accurate emissions inventories from the thousands of GDFs across
California. We all have a shared interest in ensuring evidence- and science -based
mlemaking, Unlike iminy of the policy debates that can sometimes emerge from
rulemalzin& empirical issues like this can and should be resolved definitively and
co opera tively. in order to avoid unnecessary administrative work ftxkg those C i'ssiles
later- As always, Costco remains committed to working with the District to address
these is sties quickly and efficiently, so that both the public and the regulated
community have an accurate picture of the significant emissions reduction progress at
gasoline pumps throughout the District.
The Dishict's AQNfP.. Appenax M. is avadable
i q MR!aRp e ndt x -ii i. D d f"-- fmn-- 6.
WVAV.PiJI5hXY&V-COM
4M-8492-7052.0
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2-5
W
2-7
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Ms. Kalam Cheung
July 25, 2017
Page 7
Thank you again for the opporhuuty tokvork- together with the District on this
important Rule rmision-
V ery tnily Nrours-
Michael S. IvIeDonough
WWW.PillsbWyiauv.Com
4912-202-70S2.0
24-61
Response to Comment 2-1
As noted, staff from several districts including SCAQMD participated as part of the California Air
Pollution Control Officer Association (CAPCOA) Vapor Recovery Subcommittee in the review
of CARB's revised emission factors. At the time of release, CARB is also committed to continue
its efforts to revise the newly released emission factors.
Response to Comment 2-2
SCAQMD staff agrees that the ORVR system averages a 95% control efficiency of gas tank
emissions during refueling, but disagrees that the use of a Phase II nozzle could further control all
emissions escaping from the ORVR system.
The ORVR system has mechanisms to prevent vapor within a vehicle fuel tank from escaping via
the fillpipe of the vehicle (i.e. a narrowed fillpipe to form a liquid barrier and a mechanical valve
at the end of the fillpipe). The vapor that would have otherwise escaped through the fillpipe is
directed to a carbon canister, which is the actual means of emission control of the ORVR system,
to adsorb hydrocarbons contained in the displaced vapor.
SCAQMD staff carefully reviewed the 2008 ARB study referenced by the commenter. The 2008
CARB study was conducted at an "ambient environment" (i.e. at a gasoline dispensing facility for
a rental vehicle company). While the test was designed to evaluate fillpipe emissions, the study
could not capture emissions from the on -board canister of the ORVR system. As the commenter
correctly pointed out, the top part of Table 7 lists the fillpipe emissions of refueling ORVR
vehicles. SCAQMD agrees that for emissions that pass through the fillpipe, they would be
controlled by the Phase II -equipped nozzle.
The key to the different interpretations of the 2008 ARB study between the commenter and
SCAQMD staff is that the study focuses on fillpipe emissions. As discussed above, the 2008
emission tests were conducted at the fillpipe exhaust where exhaust from the ORVR canister is not
detected. Therefore, the 2008 study does not present total refueling emissions, which include
emissions from both the fillpipe and the on -board canister for ORVR vehicles. Indeed, the bottom
part of Table 7 lists the source test results from EPA/manufactures ORVR vehicle emissions
measurement according to the Federal Test Procedure. Unlike the 2008 CARB study, which was
conducted in ambient conditions, the EPA tests were conducted using a sealed housing emissions
device (SHED), where emissions from both the fillpipe and the on -board canister were monitored.
The EPA study tested for 337 dispensing events. The fillpipe and on -board canister emissions
together averaged to 0.25 lbs per 1,000 gallons. The table further shows a standard deviation of
1.15 which indicates the control efficiency of individual vehicle tested varies significantly from
the average emissions of 0.25 lbs. per 1,000 gallons.
The SCAQMD staff believes that there is a small amount of vapor that the Phase 11 EVR system
will control during refueling of an ORVR vehicle. SCAQMD staff has been in communication
with CARB staff regarding the refueling emissions factor. Both agencies agree that additional
time is needed to better understand emission reductions from Phase II EVR for ORVR vehicles.
SCAQMD staff is recommending not to incorporate CARB's 2013 revised emission factor for
Phase II refueling of ORVR vehicles, but to continue the use of SCAQMD's current emission
factor of 0.32 lbs per 1,000 gallons for refueling. Staff is recommending the use of CARB's 2013
emission factors for all other categories (loading, breathing, spillage, and hose permeation).
24-62
SCAQMD staff is committed to continue working with CARB staff to refine the emission
estimates for Phase II refueling with ORVR vehicles and will return to the Board with future
revisions to refueling emission factors.
Response to Comment 2-3
SCAQMD staff agrees that "(ORVR) and Stage II (Phase II) are both designed to control the
vehicle refueling emissions and both are effective." As discussed in the staff report, Phase II EVR
is needed for non-ORVR vehicles to achieve the additional VOC reductions of 14.7 tons per day
in the year of 2020, and 8.8 tons per day in the year 2028 and beyond. Also, California's Phase II
program includes other emission control features, such as in -station diagnostics (ISD) and
standards for nozzle liquid retention, dripless nozzle and spillage, in addition to the control of the
vapors displaced during vehicle refueling. Thus, it achieves greater emission reductions than the
federal Stage II program requirements, and the improvement it provides is essential to meet
mandated federal ambient air quality standards. While both the ORVR and Phase II vapor recovery
systems are effective, they target different fleets (ORVR vehicles vs. non-ORVR vehicles
respectively) and different processes (ORVR controls refueling and evaporative emissions as
compared to Phase II EVR, which controls emissions at the fillpipe as well as nozzle operations
such as spillage, drips, and liquid retention, and provides early diagnostic information via ISD).
Response to Comment 2-4
Staff released the proposed emission factors for gasoline dispensing facilities in the first working
group meeting, and provided the technical justification in the second working group.
Furthermore, as discussed in Response to Comment 2-3, the 2008 CARB study only measured
fillpipe emissions, while the EPA SHED study captured both fillpipe and on -board canister (from
the ORVR vehicles) emissions. It is also important to point out that CARB's Phase II emission
factor includes pressure driven losses from the storage tanks at a GDF. Whereas, the EPA SHED
study does not include such emissions.
As discussed in Comment 2-2, SCAQMD staff is committed to working with CARB staff on the
refueling emission factor. Until then, SCAQMD staff is recommending not to incorporate CARB's
2013 revised emission factor for Phase II refueling of ORVR vehicles, but to continue the use of
SCAQMD's current refueling emission factor of 0.32 lbs per 1,000 gallons.
Response to Comment 2-5
See Response to Comment 2-3.
Response to Comment 2-6
An emission inventory is a live document that gets updated when new information is available.
For each AQMP, the emission inventory is developed using the best available information at the
time of the development. For the 2016 AQMP, the emission inventory was "frozen" in late 2015
to allow time for conducting the modeling analyses. At that time, SCAQMD staff was having
24-63
ongoing discussions with CARB staff on the concerns regarding the emission factors for refueling
and spillage.
Information necessary to produce the emission inventory for the South Coast Air Basin is obtained
from the SCAQMD and other governmental agencies, including CARB, the California Department
of Transportation (Caltrans), and the Southern California Association of Governments (SCAG).
While SCAQMD is responsible for developing the emission inventory for stationary sources,
CARB is the agency responsible for developing the emissions inventory for gasoline dispensing
facilities.
In addition, the attainment of the 2008 ozone standard mainly relies on NOx reductions. Even if
the VOC emission reductions from Phase II refueling were overestimated, the change in VOC
would not have resulted in significant impacts on the ozone concentrations in the design sites in
the attainment year. More details about the ozone modeling approach and the ozone isopleths can
be found in in the 2016 AQMP (Appendix V - Modeling and Attainment Demonstration,
Attachment 4 8 -hour Ozone Isopleths for 2031).
Response to Comment 2-7
SCAQMD staff agrees with the comment that this rulemaking should move forward and that once
CARB and SCAQMD staff agree on an emission factor for refueling, the emission factor in the
Risk Assessment Procedures can be updated at a later time. SCAQMD staff is committed to
continue working with CARB staff to refine the emission factor for Phase II refueling.
24-64
EXHIBIT 3
24-65
Scienceof t1wTotal Envirmtment650 (20 19) 2239--2250
�4
' Contents lists available at SclenceDirect
Science of the Total Environment
journal homepage: www,elsevier.com/locate/scitotenv
Vent pipe emissions from storage tanks at gas stations:
Implications for setback distances
Markus Hilpert"', Aria Maria Rule b, Bernat Adria -Mora', Tedmurtd Tiberi
Deparnnent of Envirmnnenial Health Sciences, Mailaran School of Public Health, Columbia University, New York, NY 10032, United States ofArnerica
Deparanent of Environmental Health and Engineering Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, United Status of America
ARID Technologies, Inc., Wheaton, It 60187, United States of America
H I G H L I G H T S G RAPH [CAL ABSTRACT
At gas stations, fuel vapors are released
from storage tanks through vent pipes.
We measured vent pipe flow rates and
tank pressure at high temporal resolu-
tion.
Vent emission factors were >10 times
higher than previous estimates.
Modeling was used to examine exceed-
ance of benzene short-term exposure
limits.
ARTICLE I NFO A B S T R A C T
Article history:
Received 3 July 2018
Received in revised form 11 September 2018
Accepted 23 September 2018
Available online 24 September 2018
Editor: Pavlos Kassomenos
Keywords:
Gas stations
Benzene emissions
Setback distances
Air pollution modeling
Measurements
flit%
emiss;ors 4
vent pip, 4
Gasothe 51orage Tank
At gas stations, fuel vapors are released into the atmosphere from storage tanks through vent pipes. Little is
known about when releases occur, their magnitude, and their potential health consequences. Our goals were
to quantify vent pipe releases and examine exceedance of short-term exposure limits to benzene around gas sta-
tions. At two US gas stations, we measured volumetric vent pipe flow rates and pressure in the storage tank head -
space at high temporal resolution for approximately three weeks. Based on the measured vent emission and
meteorological data, we performed air dispersion modeling to obtain hourly atmospheric benzene levels. For
the hvo gas stations, average vent emission factors were 0.17 and 0.21 kg of gasoline per 1000 L dispensed.
Modeling suggests that at one gas station, a 1 -hour Reference Exposure Level (REL) for benzene for the general
population (8 ppb) was exceeded only closer than 50 in from the station's center. At the other gas station, the
REL was exceeded on two different days and up to 160 to From the center, likely due to non-compliant bulk
fuel deliveries. A mininnun risk level for intermediate duration (>14-364 days) benzene exposure (6 ppb) was
exceeded at the elevation of the vent pipe opening up to 7 and 8 in from the two gas stations. Recorded vent
emission factors were >10 times higher than estimates used to derive setback distances for gas stations. Setback
distances should be revisited to address temporal variability and pollution controls in vent emissions.
V 2018 Elsevier B.V. All rights reserved.
Corresponding author at: Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 west 168th St., New York, NY] 0032, United
States of America.
E-utail address: [00632@coiu€mbia.edu (M. Hilpert).
iSCCi35://dOL06"g/ 1 G. i t1: G/ISCf t3tenV.2171 S.tJJ.3i}_�
0048-9697/02018 Elsevier B.V. All rights reserved.
24-66
2240
1. Introduction
Al. Hilpert et at/ Science of the Total Environment G50 (2019) 2239-2250
In the US, approximately 143 billion gal (541 billion L) of gasoline
were dispensed in 2016 at gas stations (EIA, 2017) resulting in release
of unburned fuel to the environment in the form of vapor or liquid
(Hilpert et aL, 2015). This is a public health concern, as unburned fuel
chemicals such as benzene, toluene, ethyl -benzene, and xylenes
(BTEX) are harmful to humans (ATSDR, 2004). Benzene is of special
concern because it is causally associated with different types of cancer
(IARC, 2012).Truckdrivers delivering gasoline and workers dispensing
fuel have among the highest exposures to fuel releases (IARC, 2012).
However, people living nearorworkingin retail atgas stations, and chil-
dren in schools and on playgrounds can also be exposed, with distance
to the gas stations significantly affecting exposure levels (T'erres et aL,
2010; Jo & Oh, 2001; Jo & Moon, 1999; Hajizadeh et al., 2018). A meta-
analysis (Infante, 2017) of three case -control studies (Steffen et al.,
2004; Brosselin et al., 2009; Harrison et al., 1999) suggests that child-
hood leukemia is associated with residential proximity to gas stations.
Sources of unburned fuel releases at gas stations include leaks from
storage tanks, accidental spills from the nozzles of gas dispensers
(Hilpert & Breys.se, 2014; Adria -Mora & Hilpert, 2017; Mai gesteret al.,
1992), fugitive vapor emissions through leaky pipes and fittings, vehicle
tank vapor releases when refueling, and lealry hoses, all of which can
contribute to subsurface and air pollution (1 iiipertet al., 2015). Routine
fuel releases also occur through vent pipes of fuel storage tanks but are
less noticeable because the pipes are typically tall, e.g., 4 in. These vent
pipes are put in place to equilibrate pressures in the tanks and can be lo-
cated as close as a few meters from residential buildings in dense urban
settings (Fig, 1).
Unburned fuel can be released from storage tanks into the environ-
ment through "working" and "breathing' losses (Yerushaimi & Rastan,
2014). A working loss occurs when liquid is pumped into or out of a
tank. For a storage tank, this can happen when it is refilled from a tanker
truck or when fuel is dispensed to refuel vehicles (Statistics Canada,
2009) if the pressure in the storage tank exceeds the relief pressure of
the pressure/vacuum (P/V) valve (EPA, 2008). PN valve threshold pres-
sures are typically set to around +3 and —8 in. of water column (iwc)
(7.5 and —20 hPa). However, P/V valves are not always used, particu-
larly in cold climates, as valves may fail under cold weather conditions
(Statistics Canada, 2009).
Breathing losses occur when no liquid is pumped into or out of a
tank because of vapor expansion and contraction due to temperature
and barometric pressure changes or because pressure in the storage
Fig. 1. The three vent pipes (enclosed by the red ellipse) on the right side of the
convenience store of a gas station are <10 m away from the residential building. (For
interpretation of the references to color in this figure legend, the reader is referred to
the web version of Chis article.)
tank may increase when fuel in the tank evaporates (Yerushalmi &
Rastan, 2014; EPA, 2008). Although delayed or redirected by the P(V
valve, breathing emissions can be significantand represent an environ-
mental and health concern (Yerushalnli & Rastan, 2014),
Stage I vapor recovery systems, put in place to prevent working
losses while delivering fuel to a station, collect the vapors displaced
while loading a storage tank, redirecting them into the delivery truck.
Stage JI vapor recovery systems minimize working losses while deliver-
ing gas from the storage tank to the customer's car. During Stage 11 vapor
recovery, gasoline vapors can be released through the vent pipe, if the
sum of the flow rates of the returned volume and of the fuel evaporating
within the storage tank is greater than the volume of liquid gasolinedis-
pensed (Statistics Canada, 2009). We refer to this scenario as pressure
while dispensing (PWD), In theory, a properly designed Stage II vapor
recovery system should not have working losses, although in practice
this is not typically the case (McEntire, 2000).
Regulations on setback distances for gas stations are based on life-
time cancer risk estimates. Several studies have assessed benzene can-
cer risk near gas stations (Atabi & Mirzahosseini, 2013; Correa et al.,
2012; Crtlz et al., 2007; Edokpoio et al., 2015; Edokpolo et al., 2014;
Karakitsios et al., 2007). Based on cancer risk estimations, the California
Air Resources Board (CARE) recommended that schools, day cares, and
othersensitive land uses should not be located within 300 ft. (91 in) of a
large gas station (defined as a facility with an annual sales volume of
3.6 million gal = 13.6 million L or greater) (CaIEPA,CARB, 2005). This
CARB recommendation has not been adopted by all US states, and
within states setback distances can depend on local government. Nota-
bly, CARB regulations do not account for short term exposure limits and
health effects. An important limitation of existing regulations is the use
of average gasoline emission rates estimated in the 90s that do not con-
sider excursions (CAPCOA, 1997).
The main objective of this study is to evaluate fuel vapor releases
through vent pipes of storage tanks at gas stations based on vent emis-
sion measurements conducted at two gas stations in the US in 2009 and
2015, including the characterization of excursions at a high temporal
resolution (-minutes) and meteorological conditions at an hourly tem-
poral resolution. In addition, we performed hourly simulations ofatmo-
spheric transport of emitted fuel vapors to inform regulations on
setback distances between gas stations and adjacent sensitive land
uses by comparing modeled benzene concentrations to four 60 -min
benzene exposure limits; an acute Reference Exposure Level (REL) for
infrequent (once per month or less) exposure (WHO, 2010) and
Emergency Response Planning Guidelines ERPG-1, ERPG-2 and ERPG-
3 (AIHA, 2016). Finallywe compared simulated benzene levels to a Min-
imal Risk Level (MRL) for benzene for intermediate exposure duration
(14 to 364 days) (ATSDR, 20 18) because thatduration window includes
our duration of data collection. See Table 1 for the various benzene ex-
posure limits and issuing agencies.
2. Methods
Although we provide Sl unit conversions, we report some measures
in English engineering units (ft, gal, and Ib) as regulatory agencies such
as CARB use these units.
2.1. Sites
Data for this study were obtained from vent release measurements
conducted at two gas stations as part of technical assistance to the gas
stations to quantity fuel vapor losses through the vent pipes of their
storage tanks. A motivation for conducting the measurements was to
perform a cost -benefit analysis to compare the economic losses due to
the lost fuel versus the cost of technologies that reduce the emissions.
The exact location of the two gas stations is not revealed for confidenti-
ality reasons. The gas station managers and staff who authorized the
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M. Hilpert et al. / Science of the Total Environment 650 (2019) 2239-2250
Table 1
Benzene exposure limits, to which we compared simulation results. for unit conversion, we assumed a temperatue of 25 `C, i.e., t ppm = 3194 g/m3 (CAPCOA,1997
2241
Agency
Name
Value (ppb)
Value( g/m')
Exposure duration
California Office of Environmental Health Hazard Assessment (OEHI IA)
RBL
8
26
111
American Industrial Hygiene Association (AIHA)
ERIC -1
50
159,700
1 h
AIHA
ERIC -2
150
479,100
1 h
AIHA
ERIC -3
1000
3,194,000
1 h
Agency forToxic Substances and Disease Registry (ATSDR)
MRL
6
19
14 to 364 clays
ERIC = Emergency Response Planning Guidelines. The primary focus of ERPGs is to provide guidelines For short-term exposures to airborne concentrations of acutely toxic, high-priority
chemicals,
collection and analysis of these data have not been involved in the cur-
rent manuscript.
The first gas station, "GS -MW," was located in the US Midwest and is
a 24-hour operation. The study was conducted from December 2014 to
January 2015 for20 full days, and fuel sales Vsolee were about450,000 gal
(1.7 million L) per month. Fuel deliveries to the gas station usually took
place during the nighttime. The second gas station, "GS -NW," was lo-
cated on the US Northwest coast and closed at night. Hours of operation
were between 6:00 am and 9:30 pm on weekdays and between 7 am
and 7 pill on weekends. That study was conducted in October 2009
for 18 full days, and fuel sales were Vsal,s -700,000 gal (2.6 million L)
per month.
Both gas stations are considered to be high-volume, because they
dispense >3.6 million gal of gasoline ( both regular and premium) per
year (CalEPA/GARB, 2005), and fuel was stored in underground storage
tanks (USTs), which is typical in the US. Both gas stations had Stage 11
vapor recovery installed using the vacuum -assist method. In that
method, gasoline vapors, which would be ejected into the atmosphere
as a working loss during refueling of customer vehicle tanks, are col-
lected at the vehicle/nozzle interface by a vacuum pump. The recovered
vapors are then directed via a coaxial hose back into the combined stor-
age tank ullage (]lead space) of the gas station. Stage I vapor recovery
was also used at both gas stations during fuel deliveries. Both sites had
a 3 -inch diameter (7.5 cm) single above -grade vent pipe with below -
grade manifold that connected the vent lines from several USTS; the
cracking pressures of the PN valves were set to +3 and —8 iwc (+7.5
and —20 hPa).
2.2. Ventemission measurements
To quantify evaporative fuel releases through the vent pipe of a stor-
age tank, the volumetric flow of the mixture of gasoline vapor and air
was measured in the vent pipe. A dry gas diaphragm flow meter
(American Meter Company, Model AC -250) was used. For each cubic
foot (28 Q of gas flowing through the meter, a digital pulse was getler-
ated. Every minute, the number of pulses was read out and stored to-
gether with date and time on a data logger. Gas flow meters were
obtained from a distributor calibrated and equipped with temperature
compensation and a pulse meter.
To determine the time -dependent volumetric flow rate Q(t) of the
gasoline vapor/air mixture through the vent pipe, the time series of
measured flow volumes were integrated over an averaging period (15
or 60 min) and divided by the duration of that period. Le., Q(t) is
given by the number of pulses registered by the gas flow meter in a
time window multiplied by 1 cubic foot and divided by the averaging
time. The 15 -minute averaging time was chosen to visualize time -
dependent data, while the 60 -minute averaging time was chosen be-
cause air pollution simulations were performed at that resolution.
Gas pressure p in the ullage of the storage tank was measured to as-
sess vent emission patterns. For instance, releases can occur when the
pressure exceeds the cracking pressure of the P/V valve in the vent
pipe (the dry gas flow meter was fitted with a PN valve on the outlet).
Pressure was measured with a differential pressure sensor (Cerabar
PMC 41, Endress + Hauser) every 4 s, and 2 -minute average values
were stored. The sensor range was scaled from —15 to +15 iwc (-37
to +37 hPa), with a full scale accuracy of 0.20%. We also obtained 15 -
and 60 -minute averaged tank pressure data p(t) where averages repre-
sent the means of the 2 -minute average pressure measurements taken
during each time window.
2.3. Descriptive analysis
For the 60 -minute flow rate, we calculated medians and inter quar-
tile ranges (IQRs). To illustrate diurnal fluctuations in vapor emissions,
we created box plots for the 60 -minute flow rate distribution that oc-
curred during each hour of the day. Spearman correlation coefficients
between the time series for pressure and flow rate were calculated to
evaluate whether pressure can be used to infer vent emissions.
To estimate the mass flow rate of gasoline mgo, that is released
through the vent pipe in the form of a mixture of gasoline vapors and
fresh air, we assumed, following the protocol of a study by the California
Air Pollution Control Officers Association (CAPCOA) that assessed risks
from fuel emissions from gas station (Appendix D-2 (CAPCOA, 1997)),
that the density of gasoline vapors in this mixture is given by s svl =
0.3 x 65 lb / 379 0 = 0.824 kg/m3, i.e., the molar percentages of gaso-
line and air were 30% and 70%, respectively. Then the volumetric flow
rate Q can be converted into a mass flow rate of the vaporized gasoline:
Mg. %n< Q
To arrive at vent emission factors, we firstcalculated the mean volu-
metric flow rate Q, and then the mean mass flow rate mgar gv Q.
From the latter, one can calculate the vent emission factor
EFvent mgas Vsales
For EF„ei1, CARB uses units of pounds of emitted gasoline vapors (also
called total organic gases (TOG)) per 1000 gal dispensed, or more briefly
lb/kgal where I(gal stands for kilogallons.
As we were not able to measure benzene levels in the tank ullage, we
assumed like the CAPCOA study (Section C) that the density of the mix-
ture of gasoline vapors and fresh air was ,n;xv) =1.05 Ib/ft3 =
1.682 kg/m3 and that the emitted gasoline vapor/air mixture contained
0.3% of benzene by weight (CAPCOA, 1997). Therefore, the mass flow
rate of benzene through the vent pipe was estimated as follows:
mb,m 0 003 ' Q
2.4. Airpollution modeling
We used the AERMOD Modeling System developed by the US Envi-
ronmental Protection Agency (EPA) to model the dispersion of benzene
vapors released into the environment through vent pipes of fuel storage
tanks and from other sources (Citnorelli et al., 2005). AERMOD simu-
lates atmospheric pollutant transport at a 1 -hour temporal resolution.
3D polar grids were created with the gas station in the origin and poten-
tial receptors at different radial distances (up to 170 in) and angles (10'
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2242 Al. Hil pert el al. / Science of theTotal Environmenl650 (2019) 2239-2250
increments). The grids were placed attheground level (z =0 m), in the
breathing zone (z = 2 m), and at the 2nd floor level (z = 4 m) where
the vent pipe emissions were assumed to occur. The topography was
simplified for modeling purposes consistent with the CAPCOA study
(CAPCOA,1997), i.e., the terrain was assumed to be flat with no build-
ings present. Vent pipe emissions were modeled as a capped point
source. Chemical reactions of benzene were not modeled, as residence
times of atmospheric benzene are on the order of hours or even days
(A`i`SDR, 2007), i.e, much longer than the travel time of benzene vapors
across the 340-m diameter model domain,
For the period of time when vent emission measurements were
made, we obtained meteorological data at a 1 -hour temporal resolution
that are representative for the geographic locations of the two gas sta-
tions. Table SI -1 provides descriptive statistics of that data. The time se-
ries were used in AERMOD to model the transport of benzene in the
temporally varying turbulent atmosphere. We also used the 1 -hour av-
erage time series of benzene emission rates (Eq. (3)) as an input into
AERMOD.
To evaluate at each grid pointwhether OEHHA's acute RELorAIHA's
ERPG levels were exceeded at least once, we determined maximum 1 -
hour average benzene concentrations that were simulated for about
three weeks. To evaluate how often the OEHHA REL was exceeded at
each grid point in the breathing zone, we created plots indicating the
number of exceedances and the day when the maximum benzene
level was observed.
To facilitate comparison to published benzene measurements
around gas stations, we determined for each simulated radial distance
from a gas station the mean of the average concentrations simulated
for each ten degree increment on the radius around the gas station.
3. Results: vent releases
3.1. Times series of tank pressure and ow rate
Fig. 2 shows the time -series data for the volumetric flow rate Qof the
gasoline vapor/air mixture through the vent pipe and tank pressure p
that we collected at the two gas stations. At GS -MW, little vapor was
typically released in the late night and in the very early morning,
while releases were generally much higherduring the daytime and eve-
nings, presumably when more fuel was dispensed (Fig. 2a). Occasion-
ally, no vapor releases occurred for several howl. While we do not
have access to time of fuel delivery records, field visits indicate that
time periods with no releases coincide with fuel deliveries. For instance,
fuel delivery likely occurred on january 6 at 7 pm (see Fig. 3a; an ampli-
fication of data shown in Fig. 2a). As a result, the UST pressure dropped
by about 10 hPa, far below the cracking pressure of the P/V valve. The
decreased gas pressure in the ullage increased until the cracking pres-
sure of the P/V valve was reached. A very small vapor release
(-2 L/min) was observed briefly on the next day at 2 am. The vapor
flow rate becomes relatively large again, -12 L/min, only after 6 am,
i.e., 11 h after fuel delivery.
Fig, 3b amplifies a major vapor release at GS -MW. The UST pressure
significantly exceeded the cracking pressure of the P/V valve and rose
rapidly up to 37 hPa, which coincides with vapors being released at a
high flow rate (15 -min average) of about 470 L/min.
At GS -NW, vapor releases followed a quite different pattern (Fig. 2b).
Contrary to GS -MW, vapor releases occurred in a cyclical pattern, and
tended to be higher in the late night and in the very early morning
when the gas station was closed
3.2. Statistics of vapor emissions
The average volumetric flow rateQ through the vent pipe for the en-
tire period of time during which measurements were taken was Q =
7.9 L/min for GS -MW and Q = 15.4 L/min for GS -NW, which is
consistent with the higher sales volume of GS -NW. These emis-
sions consist of a mixture of gasoline vapors and air. Using Eq. (1), the
volumetric flow rates were converted into average mass flow rates of
gasoline: ms. = 0.39 kg/h for GS -MW and ms,, = 0.76 kg/h for GS -
NW. Using Eq. (2), we determined a vent emission factor El`vcnt=
0,17 kg per 1000 L = 1.4 lb/kgal for GS -MW and EF,,ent=
0.21 kg per 1000 L = 1.7 lb/kgal for GS -NW.
The medians (IQRs) for the 60 -minute averaged flow rate Q (L/min)
were 6.1 (1.9, 10,9) for GS -MW and 16.0 (12.7, 18A) for GS -NW. For GS -
MW, the mean is larger than the median, indicating a more skewed dis-
tribution of flow rates when compared to GS -NW. Also the first quartile
is much lower than the median for GS -M W, indicating that there are pe-
riods of time during which little emissions occurred, Conversely, GS -
NW was releasing emissions more consistently.
Fig. 4a shows boxplots illustrating the distribution of flow rate Qfor
each hour of the dayat GS -MW. Less vapor was released between 10 pm
and 4 am, even though the gas station was in operation, albeit at lower
activity levels. The flow rate Q at GS -NW (Fig. 4b) had fewer outliers,
and the highest outlier was an order of magnitude lower than the
highest one at GS -MW. Emissions were highest between 1 and 3 am,
when tine gas station was closed.
The Spearman correlation coefficients between tank pressure p and
vent flow rate Q were r = 0.58 for GS -MW and r = 0.85 for GS -NW.
Thus, vent releases are moderately and strongly correlated with tank
pressure, respectively. Table 2 summarizes statistical properties of
vent emissions at the two gas stations.
4. Results: air pollution modeling
4.1. Emission sources and rates
Vent pipe emissions of benzene were.modeled at a 1 -hour temporal
resolution.as described in Section 2.4. However, they are not the sole
source of gasoline emissions at gas stations. Accidental spills from noz-
zles regularly occur near the dispensers, "refueling losses" can occur
when gasoline vapors are released from the vehicle tank during
refueling due to the rising liquid levels in the tanks, fuel vapors are re-
leased from permeable dispensing hoses, and "fugitive" or leakage
emissions occur with driving force derived from storage tank pressure.
In Section A of Supporting material, we detail how these other emission
sources were modeled. Table 3 summarizes estimated mean emission
rates. Note that the vent pipe losses are much greater than otherlosses.
4.2. Predicted benzene levels
Fig, 5 shows for both gas stations and at each grid point the maxi-
mum 1-houraverage benzene concentration observed during the simu-
lated periods in time. Benzene levels depend significantly on elevation
within a 50 -meter radius around the centers of the gas stations. Close
to the centers of the gas stations, benzene levels are higher at the 4-m
elevation and at ground level due to vent pipe emissions, which repre-
sent the largest emission source (Table 3). Further than 50 m away
from the center, the vertical concentration differences become less obvi-
ous due to dispersion causing vertical mixing of benzene vapors.
At GS -MW, the 1 -hour acute REL of 26 g/m3 was exceeded
160 m away from the center of the gas station, at `the location
(x = 158 m, y = 28 m) both at ground level and in the breathing
zone. At grid points with a distance >50 m from the center of the
gas station, the REL was exceeded at most once (Fig. SI -1a). How-
ever, the exceedance at different grid points did not occur on the
same day (Fig. SI -lb). Within the 20 days during the measure-
ment campaign, exceedances occurred on the 4th and 13th of
January.
At GS -NW, the furthest REL exceedance occurred at 50 m from the
center of the gas station at the grid point (x = —38 in, y = 32 m) as
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Al. Hil pert et al./ Science of the Total Environment oo (2019)2239-2250
tit ra
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M. Hilpert et nl. / Science of the Total Environment 650 (2019) 2239-2250
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Fig. 3. Amplifications of time series data (15 -minute averages) for GS -MW. (a) Tank pressm e p became negative after fuel delivery. Asa result, vent emission ceased for several hours.( b) A
major vapor release (burst) likely occurred when the cracking pressure of the P/V valve was significantly exceeded at around 9 pm during non-compliant bulk fuel delivery.
24-71
a
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Fig. 4. Distribution of vent emissions Q observed foreach hour of the day
at (a) GS -MW ( insert shows the IQRs ofQ] and (b)
GS -NW gas stations. In (a), outliers make it difficult to recognize
variations in median hourly emissions. We therefore
plotted in the inset
only the IQRs. Boxes indicate median and IQR, whiskers values within 1.5 the IQR, and asterisks outliers.
24-71
M. Hilpert et nl. / Science of the Total Environment 650 (2019) 2239-2250
2245
Table 2
Summary of gas station characteristics and vent emissions.
Sales volume 1:"GS-Mw
GS -NW
Units
Volumetric flow rates
450,000
700,000
gal/month
(of gasoline vapor/air mixture)
Meana
7.9
Median (IQR) of 60 -min average
6.1 (1 .9, 10,9)
15.4
L/min
Maximum of 60 -min average250
16.0 (12.7, 18.4)
L/min
Vent emission factor EF,.,.
7.9
32,1
L/min
Mass flow rates of gasoline (w/o air)
1.7
Ib/kgal
Mean mem
0.39
0.76
Maximum of60-lain average72.3
kg/h
Correlation coefficient
1.6
kg/h
Between Qand p
0.58
0.85
shown in Fig. SI -2a. At a distance of 40 nn, the REL was exceeded three
times at one grid point (260° angle), and at 35 m four times at two
grid points (250° and 260° angles) (Fig. SI -2b). At a distance of 20 nn,
the RELwas exceeded at30 (outof36) grid points, and on nine different
days.
Average benzene levels are shown in Fig. 6 for both gas stations. The
MRL is exceeded at the elevation of the vent pipe opening, z = 4 ill, up
to 7 in away from for GS -MW and up to 8 in fi,om CS -NW. Fig. 7 shows
the average benzeneconcentration as a function ofdistanceatan eleva-
tion of 2 m. Close to the center, benzene levels first increase and then
decrease.
5. Discussion
5.1. Ventemissionfactots
We present unique data on vent emissions from USTS at two gas sta-
tions. Emissions can be compared to vent losses assumed by CAPCOA
(CAPCOA, 1997). For a gas station with Stage 1 and II vapor recovery tech-
nology and a P/V valve on the vent pipe of the UST (Scenario 6B), tine
CAPCOA study assumed loading losses of 0.084 and breathing losses of
0.025 Ib/kgal dispensed. The total loss of gasoline through the vent pipe
is the sum of the two and amounts to a vent emission factor EG,m„
0.109 Ib/kgal. Based on actual measurements in two fully functioning
US gas stations, we obtained EF,.,,,, values of 1.4 Ib/kgal for GS -MW and
1.7 Ib/legal for GS -NW, more than one order of magnitude higher than
the CAPCOA estimate. While the difference between out- measurements
and the CAPCOA estimates may appear surprising, it is important to con-
sider that the CAPCOA estimates are based on relatively few measure-
ments and some unsupported assumptions (Aerovironment, 1994),
particularly with regard to uncontrolled emissions due to equipment fail-
ures or defects (Appendix A-5 (CAPCOA, 1997)).
5.2. Pressure measurements
Tank ullage pressure p was moderately to strongly positively cor-
related with vent flow rate Q likely because exceedance of the crack-
ing pressure of the PN valve causes a vent release. Thus pressure
Table 3
Mean benzene emission rates lab_ for the two gas stations.
Emission source Benzene emissions (mg/s)
Gas station GS -MW GS-Nw
Vent pipe0.80 1.55
Spillage 0.39 0.65
Refueling 0.41 0.69
Hose permeation 0.06 0.10
r otai 1.67 2.90
measurements can be used to infer vent releases. Real-time detec-
tion of equipment failures and leaks via so-called in -station diagnos-
tics systems is based on our observed correlations between p and Q.
5.3. Diunlal uctuations in vent emissions
Diurnal vent emissions were quite different at the two gas stations.
At GS -MW, a 24-hour operation, vent emissions were high during the
daytime, presumably due to PWD. Emissions ceased at night, likely be-
cause less gasoline was dispensed and fuel deliveries with relatively
cool product were frequent, Evaporative losses could also have been
lower at night because the cooler delivered fuel would cause slight con-
traction of the liquid phase with corresponding growth in the ullage vol -
nine while at the same time lowering the vapor pressure of gasoline in
the UST.
At GS -NW, vent pipe releases occurred most of the time, during the
daytime when fuel was dispensed (PWD) and at nightwhen the gas sta-
tion was closed. Vent releases were higher when the gas station was
closed, suggesting that during the day -time Stage 11 vapor recovery re-
sulted in the injection of vapors into the storage tank that were not
completely equilibrated with the liquid gasoline. During night-time,
the gradual equilibration of unsaturated air in the ullage of the UST
with gasolinevapors could then have caused exceedance of the cracking
pressure of the P/V valve and consequently vapor release. It seems
counterintuitive that less nighttime emissions occurred at the gas sta-
tion where fuel was dispensed. However, while fuel is being dispensed,
the outgoing liquid creates additional ullage volume, and depending on
excess air ingestion rate, a negative pressure could result that lowers
vent pipe emissions.
Dispensing fuel to customer vehicles and the associated Stage 11
vapor recovery system interact with vent emissions and can even
cause vent emission during PWD, because the vacuum -assist method
can negatively interfere with Onboard Refueling Vapor Recovery
(ORVR) installed in customer vehicles (EPA, 2004). However, Stage II
vapor recovery is not obsolete. It can be used in conjunction with
ORVR to minimize exposure of gas station customers and workers to
benzene due to working losses (Cruz -Nunez et a)., 2003), particularly
when customer vehicles are not equipped with ORVR (e.g., older vehi-
cles, boats, motorcycles) o- small volume gasoline containers are
refueled. Enhanced Stage Il vapor recovery technology can significantly
reduce vapor emissions both at the nozzle and from UST vent pipes
(CARR, 2013).
5.4, fuel deliveries and accidental vent releases
Based on observations and interpretation of time series of the tank
pressure data, it is likely that the peak vent emissions (e.g., Fig. 3b)
were partly due to non-compliant bulk fuel drops where the Stage I
vapor recovery system either was not correctly hooked up by the deliv-
ery driver or to hardware problems with piping and/or valves. This
24-72
2246
15(
mo
:0
40
a:.
ao
25
125
2n
t.5
to
5
-150 -too -50 0 .- 0
50 I00 iso -150 -to([ -50 0 50 loo 150
I SO
A5
104 $�
Iffi ICA1 i
�a
0
50 I
! 140
OI t t 51) as
Lam, IZU;
N -'o
0 .,.3 1
25
so sn
So i i 20
f ce i
f00 - 15
40 10's �
•150 � �I
i r"U i
� •ISO 5
-150 •100 •50 0 50 I00 150 •150 -100 -50 0 50 100 150 0
Fig. S. Modeled maximum benzene concentrations for GS -MW and GS -NW at three different elevations z. The x- andy-axes indicate horizontal coordinates in metels.The color indicates
benzene levels in units of 9/in'.Leftcolu ' In": time series of benzene ernission rates were used. Right column: average benzene emission rate was used in tile modeling. The white isoline
indicates OEHHA'sacute REL of26 gIrn'=8 ppb.
conjecture is consistent with typical US storage tank volumes (-•10,000 assumed working loss of 38,000 L. This could be due to a fuel delivery,
to 30,000 gal). Assuming that Phase I vapor recovery did not work at all which involved dropping fuel from multiple compartments of a tanker
and that 10,000 gal (-38,000 L) of fuel were delivered, the working loss truck, with the vapor return hose not being correctly hooked up for
(volume of gasoline vapor/air mixture released to the atmosphere only some of the emptied compartments.
through the vent pipe) is 38,000 L. It is also reasonable to assume that At GS -MW, UST pressure decreased after fuel delivery (causing vent
delivery lasted less than 1 h. According to Table 2, the maximum hourly emissions to cease for several hours) during the climatic conditions
flow rate through the vent pipe was 250 L/min at GS -MW, which would prevalent during the observation period, behavior not observed at GS -
result in a maximum cumulative vapor release of 15,000 L within this NW. In practice, it is possible to observe both positiveand negative pres-
hour.The measured maximum cumulative release underestimates the sure excursions, even duringthe same fuel delivery (when multiple fuel
24-73
I
�l
7
r`
� r
:0
40
a:.
ao
25
125
2n
t.5
to
5
-150 -too -50 0 .- 0
50 I00 iso -150 -to([ -50 0 50 loo 150
I SO
A5
104 $�
Iffi ICA1 i
�a
0
50 I
! 140
OI t t 51) as
Lam, IZU;
N -'o
0 .,.3 1
25
so sn
So i i 20
f ce i
f00 - 15
40 10's �
•150 � �I
i r"U i
� •ISO 5
-150 •100 •50 0 50 I00 150 •150 -100 -50 0 50 100 150 0
Fig. S. Modeled maximum benzene concentrations for GS -MW and GS -NW at three different elevations z. The x- andy-axes indicate horizontal coordinates in metels.The color indicates
benzene levels in units of 9/in'.Leftcolu ' In": time series of benzene ernission rates were used. Right column: average benzene emission rate was used in tile modeling. The white isoline
indicates OEHHA'sacute REL of26 gIrn'=8 ppb.
conjecture is consistent with typical US storage tank volumes (-•10,000 assumed working loss of 38,000 L. This could be due to a fuel delivery,
to 30,000 gal). Assuming that Phase I vapor recovery did not work at all which involved dropping fuel from multiple compartments of a tanker
and that 10,000 gal (-38,000 L) of fuel were delivered, the working loss truck, with the vapor return hose not being correctly hooked up for
(volume of gasoline vapor/air mixture released to the atmosphere only some of the emptied compartments.
through the vent pipe) is 38,000 L. It is also reasonable to assume that At GS -MW, UST pressure decreased after fuel delivery (causing vent
delivery lasted less than 1 h. According to Table 2, the maximum hourly emissions to cease for several hours) during the climatic conditions
flow rate through the vent pipe was 250 L/min at GS -MW, which would prevalent during the observation period, behavior not observed at GS -
result in a maximum cumulative vapor release of 15,000 L within this NW. In practice, it is possible to observe both positiveand negative pres-
hour.The measured maximum cumulative release underestimates the sure excursions, even duringthe same fuel delivery (when multiple fuel
24-73
M. Hilpert et al. / Science of dhe Total Environment 650 (2019)2239-2250
GS -MW GS -NW
22.47
compartments of tanker trucks are unloaded), when Stage I vapor re
covery is in place (personal observation by TT).
5.5. Exceedance of 1 -hour exposure limits
AERMOD air pollution modeling suggests that at Gs -Mw the 1 -
hour acute REL was exceeded at one grid point 160 m (525 ft) from
the center of the gas station once in 20 days (Fig. 5). This distance
is larger than the 300 -ft (91 m) setback distance recommended by
CARB for a large gasoline dispensing facility (CMEFA;CARB, 2005).
Assuming the gas station's fence line is <225 ft. (69 m) from its cen-
ter (where the vent pipe wa's assumed to be located), our study
shows that sensitive land uses at a distance further than 300 ft
from the fence line of the gas station would represent a health con-
cern despite compliance with the CARB guidelines because of non-
compliance with the acute REL.
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Af. Hilpert et al. / Science ojdte Total Environment 650 (2019) 2239-2250
C
0 2
ro
0.5
0
I I i I
1 20 40 60 80 100 120 140 180
Distance from center of gas station (m)
Fig. 7. Mean benzene concentrations as a function of distance from the center of the gas
stations.
At any location further than 50 in from the gas station's center, the
REL was exceeded at most once during the 20 -clay measurementcam-
paign (Fig. Sl -1 a). However, exceedance occurred at several locations,
and on two different days (Fig. SI -1 b), E.g., at a distance of 120 in from
the center, the REL was exceeded at three grid points, and the number
of grid points increased with closer proximity to the gas station. This
suggests that it was notjust a single worst-case scenario or a single ac-
cidental vapor release that led to REL exceedance; rather exceedance
may occur more frequently than is anticipated. Prevalent wind direc-
tions during the measurement campaign explained the directional pat-
terns of exceedances (see the wind rose in Fig. SI -3a).
At GS -NW, despite its higher sales volume, the REL was exceeded
only closer than 50 m Front the gas station's center. However, exceed-
ance occurred much more frequently (Fig. SI -2), likely because of the
higher sales vola ne of GS -NW. Again, the wind rose for GS -NW
(Fig. SI -3b) explains spatial patterns of REL exceedance.
None ofAIHA's three ERPG levels were exceeded, meaning that indi-
viduals, except perhaps sensitive members of the public, would not
have experienced more than mild, transient adverse health effects.
5.6. Average benzene levels
The initial increase in average benzene levels when moving away
from the gas stations' centers (Fig. 7) is likely due to the vent emissions
(at 4 m) which represent the largest benzene source, and which require
a certain transport distance until they reach the 2-m level through dis-
persion. Furtheraway from the gas station, benzene levels are higher for
GS -NW than forGS-MW likely because of the higher sales Volume ofGS-
NW. However, close to the center, benzene levels are higher at GS -MW.
This can be attributed to the higher wind speeds at GS -NW (Table SI -1),
which result in greater initial dilution of emitted pollutants in the in-
coming airstream and also in greater subsequent pollutant dispersion.
Modeled average benzene concentrations are generally lower (-10
g/m3 or less) than those measured in the surroundings of gas stations,
likely because oursimulations do not account for traffic -related air pol-
lution (TRAP). For instance, a study published by the Canadian petro-
leum industry found average benzene concentrations of 146 and
461 ppb (466 and 1473 g/m3) at the gas station property boundary
in summer and winter, respectively (Akland, 1993), values orders of
magnitudes higher than ours. A South Korean study examined outdoor
and indoor benzene concentrations at numerous residences within
30 m and between 60 and 100 in of gas stations and found median out-
door benzene concentrations of 9.9 and 6.0 g/1113, respectively (jo &
Moon, 1999), while we simulated benzene levels on the order of 1 g/
m3 (Fig. 7). In a study on atmospheric BTEX levels in an urban area in
Iran, the three highest BTEX levels were measured near gas stations
(-150 to away); the measured benzene levels (64 ± 36, 31 f 28, 52
f 26 g/m3) were again much higher than ours simulated at that dis-
tance, likely due to TRAP. Our modeled average benzene levels at a dis-
tance of about 50 n1 are on the same order as background benzene levels
of 1.0 g/m3 that were measured in 2010 in the National Air Toxics
Trend Sites (NATTS) network of 27 stations located in most major
urban areas in the US (Strum & Scheffe, 2016). However, our modeled
levels at a distance of 170 m were 0.07 at GS -MW and 0.12 at GS -NW,
a non -negligible addition to urban background levels.
At both gas stations, the MRL was exceeded at the level of the vent
pipe opening in the vicinity of the gas stations, up to 7 m away from
the vent pipe at GS -MW and 8 m at GS -NW. Therefore there might be
an appreciable risk of adverse noncancer health effects for individuals
living at the 2nd -floor level relatively close to high-volume gas stations
such as GS -MW and GS -NW. '
5.7. Limitations
A limitation of our study is that data were collected only in fall and
winter. Results cannot be easily extrapolated to other seasons, because
vent pipe emissions are seasonally dependent, e.g., due to seasonallyde-
pendent gasoline formulations and meteorological conditions. How-
ever, modeled exceedance of the OEHHA acute REL in the winter
season is already of concern, because that REL was developed for once
per month or less exposures.
Another limitation is that we did not directly measure benzene
levels in theventpipe, and instead made assumptions aboutvaporcom-
position that were also made in the CAPCOA study (CAPCOA, 1997) of
gas station emissions. In practice it may be difficult to obtain permission
from gas station owners to treasure benzene levels directly.
In part because we did not want to reveal the locations of the gas
stations, we did not use site-specific topography information in the air
dispersion modelingand instead assumed Flat terrain. While this simpli-
fication results in less accurate air pollution predictions for the two sites,
using a "generic" gas station is perhaps more representative of othergas
station sites, and is consistentwith an approach used in a previous study
(CAPCOA, 1997).
Finally, our study did not predict benzene levels in indoor environ-
ments. Even though indoor air pollution levels may substantially differ
from outdoor levels dile to indoorsources (e.g,, smoking, photocopying)
(EI-Hashemy & Ali, 2018), our study can still inform exposure levels in
indoor environments as outdoor sources may be the main contributors
to indoorair pollution, e.g., in buildings situated in urban areas and close
to industrial zones or streets with heavy traffic (Jones, 1999). This is rel-
evant to workers and customers in C -stores or other fast-food/gasoline
station combination facilities.
6. Conclusions
Our study is to the best of our knowledge the first one to (1) report
hourly vent emission data for gasoline storage tanks in the peer-
reviewed literature and (2) use these data in hourly simulations of at-
mospheric benzene vapor transport This allowed us to examine poten-
tial exceedance of short -tern exposure limits for benzene, Prior studies
including CAPCOA's (CAPCOA, 1997) could not do so as average emis-
sion rates were used (only meteorological data was used at an hourly
resolution).
0111 -findings support the need to revisit setback distances for gas sta-
tions, which are based on >2 -decade old estimates of vent emissions
(Aerovirontnent,1994). Also, CARB setback distances are based on a bi-
nary decision, related to whether the gasoline sales volume Vsoles is
>3.6 million gal per year. Our data support, however, that setback
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M. Hilpert et al. / Science of the Total Environnient 650 (2019) 2239-2250
distances should be a continuous function of sales volumeVSales and also
include the type of controls installed at the facility. Setback distances
should also address health outcomes other than cancer. OEHHA's
acute REL forbenzene could be used to inform setback distances as it ac-
counts for non -cancer adverse health effects of benzene and its metab-
olites (Gudroe, 2014). ATSDR's MRL could also be considered since it is a
health -based limit.
We note that CARB recommended their setback distances in 2005,
presumably assuming pollution prevention technology yielding a 90%
reduction in benzene emissions (CaIEPA/CARB, 2005). Since then,
CARB further promoted use of second -generation vapor recovery tech-
nology (Enhanced Vapor Recovery, EVR) to reduce emissions further.
EVR includes technology that is supposed to prevent fuel vapors in
overpressurized tanks from being expelled into the atmosphere
(CARB, 2017). To that end, "bladder tanks" have been proposed, into
which the gasoline vapor/air mixture is directed as the pressure in the
combined ullage space of the storage tank increases, and from which
the mixture is redirected into the fuel storage tanks if the tillage pres-
sure becomes negative (when fuel is dispensed). The challenge with
such a system is to ensure that the bladder tankcapacity is not exceeded
by the fuel evaporation rate. Alternatively, fuel vapor release can be re-
duced by processing the fuel/air mixture through either a semi-
permeable membranevvhich selectively exhausts clean air and returns
enriched fuel vapor (Senlenova, 2004) or an activated carbon filter
which adsorbs hydrocarbons (and water vapor) and exhausts air into
the atmosphere, or by combusting the fuel/air mixture which would
otherwise be released through the P/V valve. Therefore, current CARB
setback distances might be adequate for gas stations in California but
less so for the other 49 US states, and other countries -depending on
pollution prevention technology requirements.
The largerareal extentof modeled REL exceedance at GS -MW is due
to "accidental" releases of gasoline vapors. Even though regulations ap-
pear generally not to be driven by accidental releases, at GS -NW such
releases likely led on two different days to RELexceedances at distances
beyond CARB's recommended setback distances. Policies should ad-
dress accidental fuel vaporreleases thatdepending on pollution preven-
tion technology (here Stage I vapor recovery) and its proper functioning
can occur on a frequent basis (twice at GS -MW within about three
weeks).
In future work, potential exceedance of othershorter-term exposure
limits should be examined, e.g., the 15 -minute short-term exposure
limits (STELs) and the 8-11ow' time -weighted averages (TWAs) used
for occupational exposures.
Aclmowledgements
This work was supported by NIH grant P30 ES009089 and the Envi-
ronment, Energy, Sustainability and Health Institute at johns Hopkins
University.
Competing nancial interest declaration
TT directs a company (ARID), which develops technologies for re-
ducing fuel emissions from gasoline -handling operations. AMR, BAM
and MH have no conflicts of interests to declare.
Appendix A. Supplementary data
Supplementary data to this article can be found online at https.//doi.
org/10.1016/j.scitotenv.2018,09,303.
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EXHIBIT 4
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24-79
BAY AREA AIR QUALITY MANAGEMENT DISTRICT
375 BEALE STREET, SUITE 600
SAN FRANCISCO, CA 94105
BAAQMD Air Toxics NSR Program
Health Risk Assessment Guidelines
1. INTRODUCTION
This document describes the Bay Area Air Quality Management District's guidelines for
conducting health risk assessments. Any health risk assessment (HRA) that is required
pursuant to Regulation 2 Permits, Rule 1 General Requirements or Rule 5 New Source
Review of Toxic Air Contaminants shall be conducted in accordance with these Air
District HRA Guidelines.
In accordance with Regulation 2-5-402, the Air District HRA Guidelines generally
conform to the Health Risk Assessment Guidelines adopted by Cal/EPA's Office of
Environmental Health Hazard Assessment (OEHHA) for use in the Air Toxics Hot Spots
Program for all types of facilities except gasoline dispensing facilities (GDFs). In
addition, these guidelines are in accordance with State "Risk Management Guidance for
Stationary Sources of Air Toxics" developed by the California Air Resources Board
(ARB) and the California Air Pollution Control Officers Association (CAPCOA).
The Air District is delaying implementation of OEHHA's 2015 HRA Guidelines for
gasoline dispensing facilities while further research is conducted on the potential
impacts of OEHHA's 2015 HRA Guidelines on gasoline dispensing facilities. The Air
District HRA Guidelines for gasoline dispensing facilities are described in Section 2.2.
The Air District will periodically update these Air District HRA Guidelines to clarify
procedures or incorporate other revisions to regulatory guidelines.
2. PROCEDURES
The procedures described below constitute the Regulation 2-5-603 Health Risk
Assessment Procedures.
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2.1 Procedures for All Facilities Other Than Gasoline Dispensing Facilities
All HRAs for facilities other than gasoline dispensing facilities shall be completed by
following the procedures described in the OEHHA Health Risk Assessment Guidelines
for the Air Toxics Hot Spots Program adopted by OEHHA on March 6, 2015 and using
the recommended breathing rates described in the ARB/CAPCOA Risk Management
Guidance for Stationary Sources of Air Toxics adopted by ARB on July 23, 2015.
The OEHHA HRA Guidelines contain several sections which identify (a) the overall
methodology, (b) the exposure assessment assumptions and procedures, and (c) the
health effects data (cancer potency factors and reference exposure levels).
A summary of OEHHA's HRA Guidelines and an index of the relevant documents are
located at:
hftp://www.oehha.ca.gov/air/hot—spotslindex.htmi
OEHHA's risk assessment methodology (February 2015) is located at:
http://www.oehha.ca.gov/air/risk_assesslindex.htmi
The exposure assessment and stochastic technical support document (August 2012) is
located at:
http://www.oehha.ca.gov/air/exposure—assess/index.htmi
The Technical Support Document for Cancer Potency Factors: Methodologies for
Derivation, Listing of Available Values, and Adjustments to Allow for Early Life Stage
Exposures (May 2009) is located at:
http://www.oehha.ca.gov/airlhot—spots/tsdO52909.html
The Technical Support Document for the Derivation of Noncancer Reference Exposure
Levels (June 2008) is located at:
http://www.oehha.ca.gov/air/hot_spots/rels_dec2008.htm
The ARB/CAPCOA Risk Management Guidance for Stationary Sources of Air Toxics
(July 23, 2015) provides guidance on managing potential health risks from sources
subject to California air toxics programs and updates the Risk Management Policy for
Inhalation Risk Assessments. It is located at:
http://www.arb.ca.gov/toxics/rma/rmaguideline.htm
Sections 2.1.1 through 2.1.6 below clarify and highlight some of the exposure
assessment procedures including exposure assumptions (e.g., breathing rate and
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exposure duration), health effect values, and calculation procedures to be used for
conducting Air District HRAs.
2.1.1 Clarifications of Exposure Assessment Procedures
This section clarifies and highlights some of the exposure assessment procedures that
should be followed when conducting an Air District HRA.
2.1.1.1 Breathing Rate
On July 23, 2015, ARB adopted "Risk Management Guidance for Stationary Sources of
Air Toxics", which includes an updated Risk Management Policy for Inhalation Risk
Assessments. For the HRA methodology used in the Air Toxics NSR Program, the Air
District has conformed with these State guidelines and adopted the exposure
assessment recommendations made by ARB and CAPCOA. The policy considers the
new science while providing a reasonable estimate of potential cancer risk for use in
risk assessments for risk management decisions. This policy recommends using a
combination of the 95th percentile and 80th percentile daily breathing rates as the
minimum exposure inputs for risk management decisions. Specifically, the policy
recommends using. the 95th percentile rate for age groups less than 2 years old and the
80th percentile rate for age groups that are greater than or equal to 2 years old.
To assess potential inhalation exposure to offsite workers, OEHHA recommends
assuming a breathing rate of 230 L/kg-8 hours. This value represents the 95th
percentile 8 -hour breathing rate based on moderate activity of 16-70 years -old age
range.
To assess exposure to children at schools and daycare facilities, OEHHA recommends
using the 95th percentile moderate intensity breathing rates from Table 5.8 of OEHHA's
HRA Guidelines. As a default, the Air District recommends using the breathing rate for
2<16 years (520 L/kg-8 hours) for children at schools. For a more refined analysis, the
Air District will allow the use of breathing rates for other age ranges that are tailored to
the ages of the children in the specific school under evaluation.
2.1.1.2 Exposure Frequency
Based on OEHHA recommendations, the Air District will estimate cancer risk to
residential receptors assuming exposure occurs 24 hours per day for 350 days per year.
For a worker receptor, exposure is assumed to occur 250 days per year. However, for
some professions (e.g., teachers) a different schedule may be more appropriate. For
children at school sites, exposure is assumed to occur 180 days (or 36 weeks) per year.
2.1.1.3 Exposure Duration
Based on OEHHA recommendations, the Air District will estimate cancer risk to
residential receptors based on a 30 -year exposure duration. Although 9 -year and 70-
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year exposure scenarios may be presented for information purposes, risk management
decisions will be made based on 30 -year exposure duration for residential receptors.
For worker receptors, risk management decisions will be made based on OEHHA's
recommended exposure duration of 25 years.
As a default, cancer risk estimates for children at school sites will be calculated based
on a 9 -year exposure duration, such as for a K-8 school. However, this exposure
duration may be refined based on the specific school under evaluation (i.e. 6 years for a
K-5 elementary school, 4 years for a 9-12 high school, or 3 years for a 6-8 middle
school). For any analyses using an alternative to the 9 -year default duration for school
children, the breathing rate assumptions must also be adjusted in accordance with the
ages of the children in the school.
2.1.2 Health Effects Values
Chemical -specific health effects values have been consolidated and are presented in
Regulation 2, Rule 5, Table 2-5-1 Toxic Air Contaminant Trigger Levels for use in
conducting HRAs. The Air District has added the 8 -hour reference exposure levels
(RELs) adopted by OEHHA to this table. The Air District will periodically update this
table to include OEHHA's revisions to health effects values.
2.1.3 Cancer Risk Calculations
In accordance with OEHHA's 2015 HRA Guidelines, cancer risk estimates should
incorporate age sensitivity factors (ASFs) and fraction of time at home (FAH)
adjustment factors. Air District HRAs should follow OEHHA's recommended cancer risk
calculation procedures as presented in Section 8.2 of OEHHA's 2015 HRA Guidelines.
For residential exposures, the cancer risk calculations should include the most sensitive
age groups: from third trimester of pregnancy to 30 years of age for a 30 -year exposure
duration. For worker receptors, assume working begins at age 16 years.
2.1.3.1 Fraction of Time at Home (FAH)
For the initial cancer risk estimate, assume the fraction of time at home factors are
equal to one (FAH = 1.0) for the following age groups: 3rd trimester to < 2 years and 2 to
< 16 years. Use this initial analysis to assess if there are any schools within cancer risk
isopleths of one in a million or greater. If there are no schools within one in a million or
greater cancer risk isopleths, the cancer risk analysis may be refined by using the
appropriate age-specific FAH factors as identified in Table 8.4 of the 2015 OEHHA
Guidelines:
• FAH = 0.85 for age group: 3rd trimester to < 2 years;
® FAH = 0.72 for age group: 2 to < 16 years;
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• FAH = 0.73 for age group: 16 to 70 years.
2.1.3.2 Short Term Projects
In the 2015 HRA Guidelines, OEHHA recommends using actual project duration for
short term projects, but cautions that the risk manager should consider a lower cancer
risk threshold for very short term projects, because a higher exposure over a short
period of time may pose a greater risk than the same total exposure spread over a
much longer period of time. To ensure that short-term projects do not result in
unanticipated higher cancer impacts due to short -duration high -exposure rates, the Air
District recommends that the cancer risk be evaluated assuming that the average daily
dose for short-term exposure lasts a minimum of three years for projects lasting three
years or less. For residential exposures, the cancer risk calculations should include the
most 'sensitive age groups (beginning with the third trimester of pregnancy) and should
use the 95th percentile breathing rates. The Air District recommends following OEHHA
guidelines for other aspects of short term projects. In summary, the Air District
recommends:
use of actual emission rates over a minimum 3 -year duration for cancer risk
assessments involving projects lasting 3 years or less, and
• use of actual project duration for cancer risk assessments on projects lasting
longer than 3 years.
2.1.4 Noncancer Health Impacts
In accordance with OEHHA's 2015 HRA Guidelines, noncancer health impacts should
be calculated using the hazard index approach. Air District HRAs should follow
OEHHA's recommended calculation procedures for noncancer health impacts, as
presented in Section 8.3 of OEHHA's 2015 HRA Guidelines.
Regarding Section 8.3.5 of OEHHA's 2015 HRA Guidelines, the Air District does not
require inclusion of the contribution of background criteria pollutants to respiratory
health effects for Air District HRAs.
2.1.5 Spatial Averaging
Typically, HRA results for an individual receptor have been based on air dispersion
modeling results at a single point or location. In the 2015 OEHHA Guidelines (Section
4.7.3), OEHHA provides a refinement option that takes into account that people move
around within their property or workplace and do not normally remain at a single fixed
point for the entire exposure duration. This spatial averaging refinement may be used
for any chronic analysis in an Air District HRA. Spatial averaging is not appropriate for
an acute analysis.
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After the points of interest have been identified by the air dispersion modeling analysis,
the ground level air concentration for each maximum impact point may be refined by
using the arithmetic mean of the receptor concentrations identified within a spatial
average grid instead of the single maximum impact point concentration. The modeler
shall generally center the spatial average grid around the maximum impact point, but
the modeler shall also consider facility boundaries, possible receptor locations, and
predominant wind direction. This grid shall be of an appropriate shape, shall be no
larger than 400 square meters, and shall have a receptor spacing within the grid of no
less than 5 meters. Grid shape, size, and location are subject to Air District approval.
2.1.6 Stochastic Risk Assessment
For a stochastic, multipathway risk assessment, the potential cancer risk should be
reported for the full distribution of exposure from all exposure pathways included in the
risk assessment. For risk management decisions, the potential cancer risk from a
stochastic, multipathway risk assessment should be based on the 95th percentile cancer
risk.
2.2 Procedures for Gasoline Dispensing Facilities
Any HRA for a gasoline dispensing facility shall be completed by following the
procedures described in the OEHHA Health Risk Assessment Guidelines for the Air
Toxics Hot Spots Program that were adopted by OEHHA on October 3, 2003 and any
State risk assessment and risk management policies and guidelines in effect as of June
1, 2009.
The 2003 OEHHA Health Risk Assessment Guidelines contain several sections which
identify (a) the overall methodology, (b) the exposure assessment assumptions and
procedures, and (c) the health effects data (cancer potency factors, chronic reference
exposure levels, and acute reference exposure levels).
A summary of OEHHA's 2003 Health Risk Assessment Guidelines and an index of the
relevant documents are located at:
http://oehha.ca.gov/air/crnr/notice-adoption-ai r -toxics -hot -spots -program -
guidance -manual -preparation -health -risk
OEHHA's 2003 risk assessment methodology is located at:
http://oehha.ca.gov/media/downloads/crnr/hraguidefinal.pdf
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The exposure assessment and stochastic technical support document (Part IV of
OEHHA's Risk Assessment Guidelines) is located at:
http://oehha.ca.gov/media/downloads/crnr/stoch4f.pdf
The Technical Support Document for Cancer Potency Factors: Methodologies for
Derivation, Listing of Available Values, and Adjustments to Allow for Early Life Stage
Exposures (June 2009) is located at:
http://oehha.ca.gov/media/downloads/crnr/tsdcancerpotency.pdf
The Technical Support Document for the Derivation of Noncancer Reference Exposure
Levels (June 2008) is located at:
http://oehha.ca.gov/media/downloads/crnr/noncancertsdfinal.pdf
Sections 2.2.1 through 2.2.4 below clarify and highlight some of the exposure
assessment procedures including exposure assumptions (e.g., breathing rate and
exposure duration) and health effect values to be used for conducting HRAs for
gasoline dispensing facilities.
2.2.1 Clarifications of Exposure Assessment Procedures
This section clarifies and highlights some of the exposure assessment procedures that
should be followed when conducting an HRA for a gasoline dispensing facility.
2.2.1.1 Breathing Rate
On October 9, 2003, a statewide interim Risk Management Policy for inhalation -based
residential cancer risk was adopted by the California Air Resources Board (ARB) and
Cal/EPA's OEHHA (http://www.arb.ca.gov/toxics/rmpolicy.pdf). For the HRA
methodology used in the Air Toxics NSR Program for gasoline dispensing facilities, the
Air District has conformed with these State guidelines and adopted the interim exposure
assessment recommendations made by ARB and OEHHA. The Air District will continue
to use this interim recommendation for gasoline dispensing facilities even though newer
guidance has been adopted by ARB and OEHHA. The interim policy recommended,
where a single cancer risk value for a residential receptor is needed or prudent for risk
management decision-making, the potential cancer risk estimate for the inhalation
exposure pathway be based on the breathing rate representing the 80th percentile value
of the breathing rate range of values (302 L/kg-day).
To assess potential inhalation exposure to offsite workers, OEHHA recommended
assuming a breathing rate of 149 L/kg-day. This value corresponds to a 70 kg worker
breathing 1.3 m3/hour (breathing rate recommended by USEPA as an hourly average
for outdoor workers) for an eight-hour day.
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For children, OEHHA recommended assuming a breathing rate of 581 L/kg-day to
assess potential risk via the inhalation exposure pathway. This value represents the
upper 95% percentile of daily breathing rates for children.
2.2.1.2 Exposure Time and Frequency
Based on OEHHA's 2003 HRA Guidelines, the Air District will estimate cancer risk to
residential receptors for gasoline dispensing facilities assuming exposure occurs 24
hours per day for 350 days per year. For a worker receptor, exposure is assumed to
occur 8 hours per day for 245 days per year. However, for some professions (e.g.,
teachers) a different schedule may be more appropriate. For children at school sites,
exposure is assumed to occur 10 hours per day for 180 days (or 36 weeks) per year.
2.2.1.3 Exposure Duration
Based on OEHHA's 2003 HRA Guidelines, the Air District will estimate cancer risk to
residential receptors for gasoline dispensing facilities based on a 70 -year lifetime
exposure. Although 9 -year and 30 -year exposure scenarios may be presented for
information purposes, risk management decisions will be made based on 70 -year
exposure duration for residential receptors. For worker receptors for gasoline
dispensing facilities, risk management decisions will be made based on OEHHA's 2003
recommended exposure duration of 40 years. Cancer risk estimates for children at
school sites will be calculated based on a 9 -year exposure duration.
2.2.2 Health Effects Values
Chemical -specific health effects values have been consolidated and are presented in
Regulation 2, Rule 5, Table 2-5-1 Toxic Air Contaminant Trigger Levels for use in
conducting HRAs. Toxicity criteria summarized in Table 2-5-1 represent health effects
values that were adopted by OEHHA/ARB as of March 31, 2016.
2.2.3 Cancer Risk Calculations
In accordance with OEHHA's revised health risk assessment guidelines (specifically,
OEHHA's Technical Support Document (TSD) for Cancer Potency Factors, adopted
June 1, 2009), calculation of cancer risk estimates for gasoline dispensing facilities
should incorporate age sensitivity factors (ASFs).
The revised TSD for Cancer Potency Factors provides updated calculation procedures
used to consider the increased susceptibility of infants and children to carcinogens, as
compared to adults. The calculation procedure below includes the use of age-specific
weighting factors in calculating cancer risks from exposures of infants, children and
adolescents, to reflect their anticipated special sensitivity to carcinogens. OEHHA
recommended weighting cancer risk by a factor of 10 for exposures that occur from the
third trimester of pregnancy to 2 years of age, and by a factor of 3 for exposures that
occur from 2 years through 15 years of age. These weighting factors should be applied
to all carcinogens emitted from gasoline dispensing facilities. For estimating cancer risk
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for residential receptors, the incorporation of the ASFs results in a cancer risk
adjustment factor of 1.7. For estimating .cancer risk for student receptors, an ASF of 3
should be applied. For estimating cancer risk for worker receptors, an ASF of 1 should
be applied.
The cancer risk adjustment factors for gasoline dispensing facilities were developed
based on the following:
Receptor
Age Groups
ASF
Duration
Cancer Risk
Adjustment Factor
Third trimester to age 210
ears
2.25/70
0.32
Resident
Age 2 to age 16 ears
3
14/70
0.6
Age 16 to 70 ears
1
54/70
0.77
1.7
Student
Age 2 to age 16 years
3
9 years
3
Worker
Age 16 to 70 years
1
40 years
1
Since the exposure duration for a student receptor (9 years), and worker receptor (40
years), falls within a single age group, the student cancer risk adjustment factor is 3 and
the worker cancer risk adjustment factor is 1.
Cancer risk adjustment factors should be used to calculate all cancer risk estimates for
gasoline dispensing facilities.
Below is the equation for calculating cancer risk estimates for gasoline dispensing
facilities:
Cancer Risk = Dose * Cancer Risk Adjustment Factor * Cancer Potency Factor
2.2.4 Noncancer Health Impacts
In accordance with OEHHA's 2003 HRA Guidelines, noncancer health impacts should
be calculated using the hazard index approach. Air District HRAs should follow
OEHHA's recommended calculation procedures for noncancer health impacts, as
presented in Section 8.3 of OEHHA's 2003 HRA Guidelines, using the RELs identified in
Table 2-5-1.
Regarding Section 8.3.A of OEHHA's 2003 HRA Guidelines, the Air District does not
require inclusion of the contribution of background criteria pollutants to respiratory
health effects for Air District HRAs.
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3. Assessment of Acrolein Emissions
CARB has issued advisories regarding acrolein emissions data determined using CARB
Method 430 (M430): http://www.arb.ca.gov/ei/acrolein.htm. The CARB advisories state
that acrolein emissions data determined using CARB Method 430 are suspect and
should be flagged as non -quantitative. Although acrolein emission factor data is
available for several types of stationary combustion sources, this data was developed
based on source tests that utilized CARB Method 430 or equally inaccurate test
methods; therefore, the validity of this acrolein emission factor data is suspect. In
addition, the tools the Air District needs to implement and enforce acrolein emission
limits are not available due to the lack of an ARB approved acrolein test method for
stationary sources.
In consideration of this information, the Air District has determined that acrolein
emissions may be included in Air District HRAs for screening or informational purposes,
but the Air District will exclude acrolein emissions from the final HRA results on which
risk management decisions will be based.
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References
I "Air Toxics "Hot Spots" Program Risk Assessment Guidelines, The Air Toxics Hot Spots
Program Guidance Manual for Preparation of Health Risk Assessments, " OEHHA, August,
2003
2 "Air Toxics "Hot Spots" Program Risk Assessment Guidelines, Part IV. Technical Support
Document for Exposure Assessment and Stochastic Analysis ", OEHHA, September, 2000
3 "Air Toxics Hot Spots Program Risk Assessment Guideline; Technical Support Document for
Cancer Potency Factors: Methodologies for derivation, listing of available values, and
adjustments to allow for early life stage exposures", OEHHA, May, 2009
4 "Air Toxics Hot Spots Program Risk Assessment Guidelines; Technical Support Document
for the Derivation of Noncancer Reference Exposure Levels ", OEHHA, June, 2008
5 "Consolidated Table of OEHHA/ARB Approved Risk Assessment Health Values ", California
Air Resources Board, updated March 28, 2016
6 "Air Toxics Hot Spots Program Risk Assessment Guidelines; Guidance Manual for
Preparation of Health Risk Assessments", OEHHA, February, 2015
7 "Air Toxics Hot Spots Program Risk Assessment Guidelines; Technical Support Document
for Exposure Assessment and Stochastic Analysis ", OEHHA, August, 2012
8 "Risk Management Guidance for Stationary Sources of Air Toxics ", Air Resources Board
and California Air Pollution Control Officers Association, July 23, 2015
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