# MEMORANDUM

DATE: March 9, 2011

SUBJECT: HAP Content in Vapor Phase of Gasoline Residual Risk and Technology Review for the Marine Tank Vessel Loading Operations Source Category

EPA Contract No.: EP-D- 07-061; EPA Project No.: 005 RTI Project No.: 0212783.005

FROM: Karen Schaffner and Jeff Coburn, RTI International

TO: Stephen Shedd and Brenda Shine, EPA

The purpose of this memorandum is to revi ew the hazardous air pollutant (HAP) content in the vapor phase of gasoline for use in es timating emissions for the residual risk and technology review for the Marine Tank Vessel Loading Operations (MTVLO) source category for the October 2010 Risk and Technology Revi ew (RTR) proposal (75 FR 65068; October 21, 2010).

I. 

# Background

Section 112 of the Clean Air Act (CAA) establ ishes a two-stage regu latory process to address emissions HAP from stationary sources. In the first stage, sec tion 112(d) (2) requires the Environmental Protection Agency (EPA) to devel op technology-based standards, referred to as

maximum achievable control techno logy (MACT) standards, for cate gories of industrial sources. In the second stage of the regul atory process, EPA is required under section 112(f)(2) to assess

the health and environmental risks that remain after sources come into compliance with the

MACT standards.

As part of this second stage in the regulato ry process, EPA identified additional controls for certain MTVLO. Specifically, we pr oposed to require ex isting major sources 1 

# with MTVLO emissions less than 10/25 tons per year (tpy) HAP and existing major source offshore MTVLO to use submerged filling for liquids with a vapor pressure exceeding 1.5 psia (20°C) and to use vapor recovery controls if the MTVLO loads 1 million bbl/yr or more of motor gasoline.

1 

## As defined in 40 CFR 63.2, “Major source” means any stationary source or group of stationary sources located within a contiguous area and under common control that em its or has the potential to emit considering controls, in the aggregate, 10 tons per year or more of any hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants, unless the Administrator establishes a lesser quantity, or in the case of radionuclides, different criteria from those specified in this sentence.

## II. 

# Issues with HAP Content in Gasoline

A key factor affecting the cost-effectiveness of the vapor recovery system is the HAP content of the gasoline vapor. When deve loping the impacts for the proposed MTVLO standards, we used a vapor-phase HAP content of 7.3 percent for gasoline (Hester, 2006). In

their comment letter dated D ecember 6, 2010 on the RTR proposal for MTVLO, API noted that the HAP content in the vapor phase of gasoline is 3 percent HAP. API used a fixed total vapor pressure for gasoline based on old gasoline compos ition data, but set the MTBE concentration to 0 percent because use of MTBE as a gasoline additive has been phased out in the U.S. They also noted the 3 percent HAP content in the gasolin e vapor was likely biased high because the benzene concentration in the liquid phase (based on the old concentratio n data) was 1.8 percent and it should be approximately 0.5 to 0.6 percent [by volume] due to new EPA Fuel Specifications (effective in Janua ry 2011 with phase-in through 2015). 2 

# The API analysis does not account for how the total vapor pressure of the gasoline or how the relative concentrations of other HAP would be affected by thes e changes in gasoline composition.

III. 

# HAP Content Data for Gasoline

To address this issue, EPA has reviewed th e HAP content information for gasoline from several data sources, including TANKS data, EPA EPCRA Section 313 information, a recent memorandum developed for the Gasoline Dist ribution Area Source NESHAP rule, and API PERF data. The HAP content of gasoline has fluctuated over time based on petroleum industry changes, including selection of gasoline additives and regulations regarding gasoline content. In Table 1, the gasoline contents from multiple data sources are provided and the progression of changes over time is shown.

Both benzene content and MT BE content in liquid gasolin e have dropped significantly over the past several years and are expected to continue to decline. The quantity of benzene in gasoline for calendar years 2000 to 2005 has been in the range of 0.59 to 0.66 percent by volume for reformulated gasoline and in the range of 1.07 to 1.21 per cent by volume and varies across types of gasoline (EPA website). For 2005, th e average benzene content in reformulated gasoline was 0.67 percent by volume and the averag e benzene content in conventional gasoline was 1.16 percent by volume (EPA, 2008). In a 2007 data collection effort, the benzene concentration in liquid gasoline ranged from 0.25 to 1.3 percent by volume for reformulated gasoline and 0.1 to 3.6 percent by volume for co nventional gasoline (EPA , 2009a). The average benzene content in gasoline will continue to decrease from 2011 through 2015 to approximately 0.62 percent by volume, achieved through credit banking and trading, and the maximum average benzene content in gasoline, phased in from 2012 through 2016, will be 1.3 percent by volume, which cannot be met with banking credits (the MSAT rule defining these percentages was finalized in February 2007). 2 

# Refinery facilities are require d to submit annual gasoline benzene

2 

## The Mobile Source Air Toxics Phase 2 rule (MSAT2) ru le includes controls on the benzene content in gasoline, The average benzene content of a refiners total gasoline pool must be 0.62 percent by volume, with averaging, banking, and trading allowed. The average benzene content must be met on January 2, 2011 for most refiners and on January 1, 2015 for small refiners. The actual, maximum average benzene content must be 1.3 percent by volume, that cannot be met with credits. The maximum average benzene content specification must be met on July 1, 2012 for most refiners and by July 1, 2016 for small refiners. The MSAT2 rule was finalized on February 26, 2007 (72 FR 8428).

2

# pre-compliance reports to show their annual av erage benzene concentrations, and the latest available information is for reporting y ear 2009. In 2009, the annual average benzene concentrations, across all gasoline produc ts, is 1.02 percent by volume (EPA, 2009b). 3 

# In our analysis, we used a typical benzene content in reformulated gasoline of 0.8 percent by weight and of 1.4 percent by weight for conventional gasoline. 4



# Use of MTBE in gasoline has declined over th e past several years as concerns regarding MTBE in ground water have grown. While the majo rity of domestic gaso line no longer containsMTBE, gasoline produced for use in other countries may use MTBE, and these MTBEcontaining gasolines may be loaded to marine tank vessels. Because both reformulated and conventional gasolines are used in the U.S., we looked at both conventional and reformulated gasolines in the analysis.

IV. 

# Assumptions Regarding Balance Compounds in Gasoline

As the composition of HAP in gasoline cha nges, the vapor pressu re and composition of the gasoline vapors also changes. Additionally, the relative concentrations of the gasoline components are dependent on each other. For example, prior to blending with MTBE, the gasoline blending stream would have higher hexane , benzene, toluene or xylene concentrations than the blended product. If MTBE is not added, then that impacts the co ncentration of all other components. We did not have a complete anal ysis of gasoline, incl uding non-HAP volatile organic compounds (VOCs), by which to perform the analysis. API PERF data (API, 2002) appeared to provide the most recent and co mplete HAP composition for reformulated and conventional gasolines; Potter and Simmons (1998) presented fairly complete overall analysis of gasoline composition, but the data ar e slightly older than the PERF data. Each of these datasets was affected by the presence of MTBE. Conseque ntly, several assumptions were required in order to estimate the HAP content of gasolin e vapor based on the available liquid-phase composition data.

A key factor that affects the HAP content in the vapor phase is the quantity of butane in the gasoline. Due to its high volatility, sma ll changes in butane concentration can have significant affects on the the overall partial pressu re of the system. Potter and Simmons (1998) provided a value of 4.7 percent n-butane in gaso line, while API PERF provided a value of 3.23 percent n-butane on average for gasoline. Ca lculations are provided below for an n-butane content of 4.7 percent; however, we also provid e information on calculations using a value of 3.23 percent.

3 

## The annual average benzene concentration is not expected to drop to 0.62 percent by volume or lower until 2013.

4 

## The latest year for which we have specific data for both RFG and CG is for 2005. In 2005, benzene content in reformulated gasoline is 0.67 percent by volume and is 1.16 percent by volume for conventional gasoline. Using these values, the benzene content on a weighted average basis for all gasoline (one-third reformulated and two thirds conventional; see discussion later in memorandum), would be approximately 1.0, which is consistent with the average benzene content for all gasoline of 1.02 percent by volume reported in 2009. The density of benzene is greater than the average density of gasoline liquid; therefore, the benzene concentration in gasoline expressed in weight percent is greater than the benzene concentration when expressed in volume pe rcent. For reformulated gasoline, using a benzene content of 0.67 percent by volume is approximately equal to 0.80 percent by weight benzene, and for conventional gasoline, a benzene content of 1.16 percent by volume is approximately equal to 1.4 percent by weight benzene.

3

# A second factor that affects the HAP conten t in the vapor phase is the assumption of what, if any, additive is used to replace MTBE. Calculations are provided below assuming that no other additive is used to replace MTBE, and we also provide calculations assuming ethanol is used as an additive to replace MTBE.

Finally, the analysis also re quired assumptions regarding th e balance of VOC compounds in gasoline. That is, if the available compositional analysis da ta accounted for 65 percent of the gasoline liquid weight, what makes up the remaini ng 35 percent of the liquid gasoline mass? Compounds that are included in the balance compounds are iden tified in Table 2. Because gasoline composition includes a range of chemicals, we identified a surrogate for the range of compounds in the C6, C7, C8, and C9 categories. The composition of C6, C7, C8, and C9 were

based on information from Potter and Simmons (1998); the percentage of compounds in each carbon number category was summed and a surrogate compound was selected to represent the compounds in that carbon number category. For the remaining balance of other VOC compounds, heptane was selected to represent th ese compounds. The surrogates and percentages identified for C6, C7, C8, and C9 carbon number categories and other VOC are shown in Table

2.

V. 

# HAP Content Calculations for Gasoline

Review and Analysis for API provided data . We reviewed the data provided by API. API provided information showing that the su m of HAP in the vapor would be 2.56 weight percent, and we recreated the analysis, includi ng the assumptions discusse d earlier regarding the balance of VOC compounds. Tabl e 3 provides the API data on HAP content in the liquid phase of gasoline and estimates of HA P content in the vapor phase ba sed on calculations. In our estimate at 60°F, we determined that the HAP co ntent in the vapor would be 3.88 weight percent, which is somewhat similar although higher than their value. The di fference is attributable to the fact that we adjusted the total vapor pressu re of gasoline caused by the removal of MTBE, whereas API assumed that the total vapor pres sure remained constant. We also conducted analysis based on vapor pressure at 25°C (77°F). At 77°F, we estimated the HAP content in the vapor phase to be 4.36 percent by weight.

Analysis for API PERF data and Assuming No MTBE content . We also estimated the vapor compositions of gasoline based on the API PERF data, based on an assumption that MTBE would be replaced with heptane, (our surrogate VOC). Using a temperature of 77°F (25°C), EPA estimates that the sum of HAP in the vapo r is 4.96 weight percent for conventional gasoline and 3.36 weight percent for reformulated gaso line when the Potter and Simmons (1998) value for n-butane of 4.7 percent in the gasoline liquid is used. If the API PERF value of 3.23 percent n-butane in the gasoline liquid is used(API, 2002), we estimate that the sum of HAP in the vapor is 5.79 weight percent for conventional gasolin e and 3.92 weight percent for reformulated gasoline. The results for HAP content in the vapor phase are pr ovided in Table 4.

Analysis for API PERF data and Assuming Ethanol Added . Finally, we estimated the vapor compositions of gasoline based on MTBE bei ng replaced with 10 weight percent ethanol. The heptane concentration (our surrogate VOC) wa s adjusted so that the total liquid weight

4

# fraction totaled 100 percent. There was no diffe rence in the HAP conten t in the vapor phase estimates for gasoline with ethanol added vers us our surrogate VOC (heptane) because ethanol and heptane have similar vapor pressures. Thus, provided that gasoline additives used to replace MTBE do not contain significant HAP content, thes e additives are not expected to significantly alter the HAP content of the gasoline vapor; the ga soline additive that most strongly affects the HAP content of the gaso line vapor is butane.

VI. 

# Conclusions Regarding HAP Content in the Vapor

Because both reformulated and conventiona l gasolines are used in the U.S., a good estimate of the HAP in the vapor would be somewhere between these estimated values. The HAP content in the vapor phase ranges from 5.0 to 5.8 percent by weight for conventional gasoline and ranges from 3.4 to 3.9 percent by we ight for reformulated gasoline, depending on the n-butane content in the gasoline.

Based on “refinery and blender net producti on” of finished motor gasoline in 2009, approximately two-thirds of gasoline is conven tional gasoline and approxi mately one-third of gasoline is reformulated gasoline (EIA, 2009). Ba sed on “refinery net production” of finished motor gasoline in 2009, conventional gasoline account s for 97 percent and reformulated gasoline accounts for 3 percent; however, considering the production of unfinished gasoline blending stocks, reformulated gasoline and reformulated gasoline blending stocks account for 31 percent of the total gasoline and unfinished gasoline blendi ng stocks produced at re fineries in the U.S. (EIA, 2009). Table 5 highlights th e HAP content in the vapor phase for each case and provides a weighted average HAP content based on 67 pe rcent conventional gasoline and 33 percent reformulated gasoline production in the U.S., al though use of the higher value for conventional gasoline would result in slight ly higher HAP contents.

Based on our analysis, and considering the un certainty and variability in the composition of gasoline, a reasonable average value for HAP content in the vapor of gasoline (at 77°F) is 5 percent by weight.

5

## VII. 

# References

Murphy, P., Radian Corporation, to J. Durham, EPA. Memorandum on liquid HAP concentrations of various petr oleum products. August 10, 1993.

TANKS, Storage Tank Emissions Calculation Software, Version 4.09d. Emission Factor and Inventory Group, October 3, 2005.

RTI International. Draft Emission Estimati on Protocol for Petroleum Refineries. For EPA/OAQPS. December 2009.

Hester, C., MACTEC, to S. Shedd, EPA/OAQP S/SPPD. Memorandum on Review of Data on HAP Content in Gasoline. May 18, 2006.

U.S. EPA. Conventional Gasoline Para meters by Reporting Year (1997 – 2005). http://www.epa.gov/otaq/regs/fu els/rfg/properf/cg-params.htm

U.S. EPA. Reformulated Gasoline Parameters by Reporting Year. http://www.epa.gov/otaq/regs/fuel s/rfg/properf/rfg-params.htm

U.S. EPA. Composition and Behavior of Fuel Ethanol. EPA Publication No. EPA/600/R-037. April 2009.

RTI International. Emission Estimation Protoc ol for Petroleum Refine ries, Version 2.0, ICR Response Version. For OAQ PS/EPA. February 2011.

API PERF study. API Petroleum Environmental Research Forum (PERF) refinery process stream speciation study (API, 2002). 7 companies took samples on 665 streams.

Fuel Trends Report: Gasoline 1995-2005. U. S. Environmental Protection Agency. OTAQ/CISD. EPA Publication No . EPA420-R-08-002. January 2008.

Summary and Analysis of the 2009 Gasoline Benzene Pre-Compliance Reports. U.S. Environmental Protection Agency. OTAQ/CI SD. EPA Publication No. EPA-420-R-09-017.

November 2009.

Section 313 of the Emergency Planning and Comm unity Right-to-Know Act, Toxic Chemical Release Inventory, Petroleum Term inals and Bulk Storage Facilities . EPA Publication No. EPA 745-B-00-002. February 2000. See Table 3-4: Estimated Concentration Values of EPCRA

Section 313 Constituents in Crude Oil and Petroleum Products (Weight Percent).

Potter, T.L. and K.E. Simmons, Total Petroleu m Hydrocarbon Criteria Working Group Series. Composition of Petroleum Mixtures, Volume 2 . May 1998.

6

## 7 

# Energy Information Administration. Petrol eum Supply Annual 2009, Volume 1. See Table 16, Refinery and Blender Net Production of Fini shed Petroleum Products by PAD and Refining Districts, 2009.

Todd, M., API, to Air and Radiation Docket . Docket ID No. EPA-HQ-OAR-2010-0600, Letter with Comments on EPA’s Proposed Rule – Resi dual Risk and Technology Review (RTR) for

National Emission Standards for Marine Tank Ve ssel Loading Operations. Docket item no. EPA-HQ-OAR-2010-0600-0359. Dated December 6, 2010.Table 1. Data on Gasoline HAP ContentTANKS: Gasoline[T]TANKS: Gasoline(Oxygenated with MTBE)[T]TANKS: Gasoline(Reformulated with MTBE)[T]TANKS: Gasoline(Oxygenated with ethanol)[T]EPCRA Crude Oil andPetroleum Products [R] [T]February 2000Liquid, wt. % Liquid, wt. % Liquid, wt. % Liquid, wt. % [Liquid], wt %106-99-0 1,3-Butadiene540-84-1 octane)71-43-2 Benzene 1.8 1.8 1.8 1.8 1.60892-52-4 Biphenyl1319-77-3 Cresols98-82-8 Cumene100-41-4 Ethylbenzene 1.4 1.4 1.4 1.4 1.605110-54-3Hexane1 01 01 01 01 0CAS Number HAP Component110-54-3Hexane1.01.01.01.01.01634-04-4 Methyl tertiary-butyl ether 12 8.8 1591-20-3 Naphthalene0.444108-95-2 Phenol0.055100-42-5 Styrene108-88-3 Toluene 7.0 7.0 7.0 7.0 7.21201330-20-7 Xylene 7.0 7.0 7.0 7.0 7.17Sum HAP content18.20 30.20 27.00 18.20 34.09Notes:[R]: Radian Corporation reportprepared for J. Durham, EPA , regarding liquid HAP concentrationsof various petroleum products. August 10,1993.[M]: Memoradum from C. Hester, MACTEC, toS. Shedd, EPA/OAQPS/SPPD. Review of Dataon HAP Content in Gasoline. May 18, 2006.[T]: Current version of EPA's emission estimation program TANKS 4.0[E]: EPCRA table, Economic Analysis of the Final Rule to Add Certain Industry Groups to EPCRA Section 313, Appendix B "Composition ofCrude Oil and Petroleum Products." February 2000.Table 1. Data on Gasoline HAP Content106-99-0 1,3-Butadiene540-84-1 octane)71-43-2 Benzene92-52-4 Biphenyl1319-77-3 Cresols98-82-8 Cumene100-41-4 Ethylbenzene110-54-3HexaneCAS Number HAP ComponentNormal Gasoline fromGasoline DistributionNESHAP BIDOxygenated Gasoline fromGasoline Distribution NESHAPBID1994 1994Vapor, wt % Vapor, wt % Liquid, wt % Vapor, wt %0.00370.8 0.7 4.72 0.9530.9 0.91.610.6260.01 00.789 0.000650.01 0.01 0.849 0.015650.1 0.1 1.605 0.06311 61 67 1384 4282009 DraftGasoline from Draft PetroRef ProtocolDocument [R]110-54-3Hexane1634-04-4 Methyl tertiary-butyl ether91-20-3 Naphthalene108-95-2 Phenol100-42-5 Styrene108-88-3 Toluene01330-20-7 XyleneSum HAP content1.61.67.1384.4280 11.9 3.54 3.620.05 0.05 0.444 0.00060.0551 0.00013.528 0.08821.3 1.1 7.21 0.8420.5 0.4 7.17 0.2355.26 16.7638.6710.87Table 1. Data on Gasoline HAP Content106-99-0 1,3-Butadiene540-84-1 octane)71-43-2 Benzene92-52-4 Biphenyl1319-77-3 Cresols98-82-8 Cumene100-41-4 Ethylbenzene110-54-3HexaneCAS Number HAP ComponentMACTEC Summary of Data MACTEC Summary of DataMACTEC Summary ofData2005 OTAQ Data Current Data [2006] Future (2015)Vapor, wt % Vapor, wt % Vapor, wt %0.83 0.75 0.750.74 0.27 0.170.01 0.012 0.0120.14 0.053 0.0531 61 81 8110-54-3Hexane1634-04-4 Methyl tertiary-butyl ether91-20-3 Naphthalene108-95-2 Phenol100-42-5 Styrene108-88-3 Toluene01330-20-7 XyleneSum HAP content1.61.81.82.4 2.4 0.00.046 0.00027 0.000271.3 1.4 1.40.53 0.56 0.567.60 7.25 4.75Table 1. Data on Gasoline HAP Content106-99-0 1,3-Butadiene540-84-1 octane)71-43-2 Benzene92-52-4 Biphenyl1319-77-3 Cresols98-82-8 Cumene100-41-4 Ethylbenzene110-54-3HexaneCAS Number HAP ComponentLiquid, wt % Vapor, wt% Liquid, wt % Vapor, wt % Liquid, wt % Vapor, wt %0.0009 0.0103330142.94 0.7914 1.10API PERF0.2974 4.0 1.081.40.60740.8EPA FuelTrends Rpt0.36571.80.940API PERF00 00.219 0.005475 0.19API PERF0.004781 0.5 0.011.490 0.07729 1.26API PERF0.06578 1.4 0.072 221 8341 36API PERF1 1311 00 832010 Final2010 Final December 2010API Comment Letter, Att 2 (cites EPCRACrude Oil and Petroleum Products, andTANKS) [T] [E]Conventional Gasoline from PetroRefProtocol Document [P]Reformulated Gasoline from PetroRef ProtocolDocument [P]110-54-3Hexane1634-04-4 Methyl tertiary-butyl ether91-20-3 Naphthalene108-95-2 Phenol100-42-5 Styrene108-88-3 Toluene01330-20-7 XyleneSum HAP content2.221.8341.36API PERF1.1311.00.830API PERF0.00.415 0.0005961 0.21API PERF0.0003036 0.00API PERF00.0767 0.002758API PERF07.75 1.2023 7.0API PERF1.093 7.0 1.096.56 0.3133 7.31API PERF0.3514 7.0 0.3423.074.8419.233.3122.704.36

## Table 2. Balance VOC Compounds in Gasoline

Liquid, wt %



### n-Butane 4.7

isobutane 1.7

Pentane 3.9

Isopentane 7.9

2-Methylpentane (surrogate for C6 cpds) 10.08

2-Methylhexane (surrogate for C7 cpds) 7.21

2,3,4-Trimethylpentane (surrogate for C8 cpds) 3.21

1,2,4-Trimethylbenzene (surrogate for C9 cpds) 7.29

Other VOC (assume Heptane is the surrogate for Other VOC) X Balance VOC compounds HAP Component

### Table 3. Review of HAP Content Data provided by Commenter

Liquid, wt % Vapor, wt % (at 15C) Vapor, wt % (at 15C) Vapor, wt % (at 25C)

106-99-0 1,3-Butadiene

540-84-1 2,2,4-Trimethylpentane (iso-octane) 4.0 0.64 0.97 1.08

71-43-2 Benzene 1.8 0.57 0.85 0.94

92-52-4 Biphenyl

1319-77-3 Cresols

98-82-8 Cumene 0.5 0.01 0.01 0.01

100-41-4 Ethylbenzene 1.4 0.04 0.06 0.07

110-54-3 Hexane 1.0 0.51 0.78 0.83

1634-04-4 Methyl tertiary-butyl ether 0.0 0.0 0.00

91-20-3 Naphthalene 0.0 0.0 0.00

108-95-2 Phenol

100-42-5 Styrene 0.00

108-88-3 Toluene 7.0 0.62 0.94 1.09

01330-20-7 Xylene 7.0 0.17 0.27 0.34

Sum HAP content 22.70 2.56 3.88 4.36

26635-64-3 iso-octane

00098-82-8 Isopropyl benzene

00110-82-7 Cyclohexane

00064-17-5 Ethanol

Assume balance compounds/composition as follows:

CAS Number HAP Component API Comment Letter, Att 2 (cites EPCRA Crude Oil and Petroleum Products, and TANKS) [T] [E]

December 2010 Estimated values

A

ssume b

a l ance compoun d s / compos iti on as f o ll ows:

n-Butane 4.7 49.61 46.93

isobutane 1.7 6.49 6.41

Pentane 3.9 11.35 11.37

Isopentane 7.9 7.82 8.22

2-Methylpentane (surrogate for C6 cpds) 10.1 11.17 11.70

2-Methylhexane (surrogate for C7 cpds) 7.2 2.34 2.60

2,3,4-Trimethylpentane (surrogate for C8 cpds) 3.2 0.41 0.48

1,2,4-Trimethylbenzene (surrogate for C9 cpds) 7.3 0.06 0.08

Other VOC (assume Heptane is the surrogate for Other VOC) 31.31 6.88 7.84

100.00 100.00 100.00Table 4. HAP Content Calculations based on API PERF Data.

n-Butane at 4.7 percent n-Butane at 3.23 percent

Liquid, wt % Vapor, wt% Liquid, wt % Vapor, wt % Liquid, wt % Vapor, wt% Liquid, wt % Vapor, wt %

106-99-0 1,3-Butadiene 0.0009 0.01033 0.0009 0.01205

540-84-1 2,2,4-Trimethylpentane (isooctane) 2.94 0.7909 1.10 API PERF 0.2974 2.94 0.9225 1.10 API PERF 0.3472

71-43-2 Benzene 1.4 0.7263 0.8 EPA Fuel
Trends Rpt 0.4178 1.4 0.8472 0.8 EPA Fuel
Trends Rpt 0.4879

92-52-4 Biphenyl API PERF API PERF

1319-77-3 Cresols

98-82-8 Cumene 0.219 0.005472 0.19 API PERF 0.004779 0.219 0.006383 0.19 API PERF 0.005581

100-41-4 Ethylbenzene 1.490 0.07724 1.26 API PERF 0.06576 1.490 0.09010 1.26 API PERF 0.07679

110-54-3 Hexane 2.22 1.833 1.36 API PERF 1.130 2.22 2.138 1.36 API PERF 1.320

1634-04-4 Methyl tertiary-butyl ether API PERF API PERF

91-20-3 Naphthalene 0.415 0.0005958 0.21 API PERF 0.0003035 0.415 0.0006949 0.21 API PERF 0.0003544

108-95-2 Phenol API PERF API PERF

100-42-5 Styrene 0.0767 0.002757 API PERF 0.0767 0.003215 API PERF

108-88-3 Toluene 7.75 1.202 7.0 API PERF 1.093 7.75 1.402 7.0 API PERF 1.276

01330-20-7 Xylene 6.56 0.3131 7.31 API PERF 0.3513 6.56 0.3653 7.31 API PERF 0.4102

Sum HAP content 23.07 4.96 19.23 3.36 23.07 5.79 19.23 3.92

26635-64-3 iso-octane

00098-82-8 Isopropyl benzene

00110 82 7 Cyclohexane 2010 Final Reformulated Gasoline from PetroRef Protocol
Document [P]

CAS Number HAP Component Conventional Gasoline from
PetroRef Protocol Document [P] Reformulated Gasoline from PetroRef Protocol
Document [P] Conventional Gasoline from PetroRef
Protocol Document [P]

2010 Final 2010 Final 2010 Final

00110

- 82

- 7 C yc

l o h exane

00064-17-5 Ethanol

Assume balance compounds/composition as follows:

n-Butane 4.7 46.68 4.7 46.99 3.23 37.41 3.23 37.70

isobutane 1.7 6.37 1.7 6.42 1.7 7.43 1.7 7.49

Pentane 3.9 11.31 3.9 11.39 3.9 13.19 3.9 13.29

Isopentane 7.9 8.18 7.9 8.23 7.9 9.53 7.9 9.61

2-Methylpentane (surrogate for C6 cpds) 10.08 11.64 10.08 11.72 10.08 13.57 10.08 13.68

2-Methylhexane (surrogate for C7 cpds) 7.21 2.59 7.21 2.61 7.21 3.02 7.21 3.04

2,3,4-Trimethylpentane (surrogate for C8 cpds) 3.21 0.473 3.21 0.476 3.21 0.55 3.21 0.56

1,2,4-Trimethylbenzene (surrogate for C9 cpds) 7.29 0.0808 7.29 0.0813 7.29 0.09 7.29 0.09

Other VOC (assume Heptane is the surrogate for Other VOC) 30.94 7.71 34.78 8.73 32.41 9.42 36.25 10.62

76.93 95.04 80.77 96.64 76.93 94.21 80.77 96.08

100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0Table 5. HAP Content Calculations based on API PERF Data.n-Butane at 4.7 percent n-Butane at 3.23 percentConventional Gasolinefrom PetroRef ProtocolDocument [P]Reformulated Gasolinefrom PetroRef ProtocolDocument [P] Weighted averageConventional Gasolinefrom PetroRef ProtocolDocument [P]Reformulated Gasolinefrom PetroRef ProtocolDocument [P] Weighted average2010 Final2010 Final2010 Final2010 FinalVapor, wt% Vapor, wt % Vapor, wt % Vapor, wt% Vapor, wt % Vapor, wt %106-99-0 1,3-Butadiene 0.01033 0.006887 0.01205 0.008030540-84-12,2,4-Trimethylpentane (isooctane) 0.7912 0.2975 0.626634 0.9225 0.3472 0.73076071-43-2 Benzene0.7266 0.4180 0.623749 0.8472 0.4879 0.72744992-52-4 Biphenyl1319-77-3 Cresols98-82-8 Cumene 0.005474 0.004781 0.005243 0.006383 0.005581 0.006115100-41-4 Ethylbenzene 0.07727 0.06578 0.073442 0.09010 0.07679 0.085659CAS Number HAP Component110-54-3 Hexane 1.833 1.131 1.599092 2.138 1.320 1.8649701634-04-4 Methyl tertiary-butyl ether91-20-3 Naphthalene 0.0005960 0.0003036 0.000499 0.0006949 0.0003544 0.000581108-95-2 Phenol100-42-5 Styrene 0.002758 0.001838 0.003215 0.002144108-88-3 Toluene 1.202 1.093 1.165704 1.402 1.276 1.35964001330-20-7 Xylene 0.3133 0.3514 0.325985 0.3653 0.4102 0.380239Sum HAP content4.96 3.36 4.43 5.79 3.92 5.17

# Appendix A

TANKS, Storage Tank Emissions Calculation Software, Version 4.09d. Emission Factor and Inventory Group, October 3, 2005.

## Sum HAP 27 

## TANKS v4.09d Data on Gasoline HAP Content

HAP (and other compounds) Liquid wt %

Gasoline Benzene 1.8 Ethylbenzene 1.4

Hexane (

‐ n) 1.0

Toluene 7.0 Xylene (

‐ m) 7.0

Sum HAP 0.182

Gasoline (Oxygenated with MTBE) Benzene 1.8 Ethylbenzene 1.4

Hexane (

‐ n) 1.0

MTBE 12

Toluene 7.0 Xylene (

‐ m) 7.0

Sum HAP 0.302

TANKS also specifies the following compounds:

iso

‐ octane 4.0 Isopropyl benzene 0.5 Cyclohexane 0.24

Gasoline (Reformulated with MTBE) Benzene 1.8 Ethylbenzene 1.4

Hexane (

‐ n) 1.0

MTBE 8.8

Toluene 7.0 Xylene (

‐ m) 7.0

Sum HAP 0.27

TANKS also specifies the following compounds:

iso

‐ octane 4.0 Isopropyl benzene 0.5 Cyclohexane 0.24

Gasoline (Oxygenated with ethanol) Benzene 1.8 Ethylbenzene 1.4

Hexane (

‐ n) 1.0

MTBE 8.8

Toluene 7.0 Xylene (

‐ m) 7.0

Sum HAP 0.27

TANKS also specifies the following compounds:

iso

‐ octane 4.0 Isopropyl benzene 0.5 Cyclohexane 0.24

Ethanol 5.6

# Appendix B

Section 313 of the Emergency Planning and Comm unity Right-to-Know Act, Toxic Chemical Release Inventory, Petroleum Term inals and Bulk Storage Facilities . EPA Publication No. EPA 745-B-00-002. February 2000.

# Table 3-4

Estimated Concentration Values of EPCRA Section 313 Constituents
in Crude Oil and Petroleum Products (Weight Percent)

EPCRA Section

313 Chemical **De Minimis**

Level* Crude Oil Gasoline

(Various

Grades) No.2 Fuel

Oil/ Diesel

Fuel Jet Fuel

(JP-4) Kerosene Lubricating

Oil No. 6

Fuel Oil Aviation

Gasoline

Benzene 0.1 0.446 R 1.608 R 8.0E-04 A 1.0 A 0.004 A N/A 0.001 0.515 R

Biphenyl 1.0 0.060 R 0.010 R 0.100 0.120 R 0.120 R N/A N/A N/A

Bromine 1.0 N/A N/A N/A N/A N/A N/A 3.0E-06 N/A

Chlorine 1.0 N/A N/A N/A N/A N/A N/A 0.0131 D N/A

Cyclohexane 1.0 0.700 0.240 N/A 1.240 N/A N/A N/A N/A

Ethylbenzene 1.0 0.346 R 1.605 R 0.013 A 0.50 A 0.127 A N/A 0.0022 0.432 R

n-Hexane 1.0 2.463 R 1.0 T 1.0 A 1.5 T 0.005 A N/A N/A 0.126 R

MTBE b 1.0 N/A 15.00 N/A N/A N/A N/A N/A N/A

Naphthalene 1.0 0.219 R 0.444 R 0.550 0.468 R 0.733 R N/A 0.10 0.10 R

Phenanthrene 1.0 N/A N/A 0.125 N/A N/A N/A N/A N/A

Phenol 1.0 0.323 0.055 0.064 N/A 0.770 N/A N/A N/A

PACs e 0.1 0.0004 N/A N/A N/A N/A N/A 1.13 N/A

Styrene 0.1 N/A N/A @ 0.032 R N/A N/A N/A N/A N/A

Toluene 1.0 0.878 R 7.212 R 0.032 A 3.20 A .13 T N/A 0.006 7.327

1,2,4-Trimethylbenzene 1.0 0.326 2.50 ‡ 1.0 ‡ N/A N/A N/A N/A N/A

Xylene 1.0 1.420 R 7.170 R 0.290 A 3.20 A 0.31 A N/A 0.013 2.204

Antimony a 0.1 1.0E-05 N/A N/A N/A N/A N/A 1.0E-06 N/A

Arsenic a 0.1/1.0 c 2.0E-05 N/A 8.5 E-06 N/A N/A N/A 3.06E05 D N/A

Beryllium a 0.1/1.0 c 2.0E-07 N/A 5.0 E-06 N/A N/A N/A 2.7E06 D N/A

Cadmium a 0.1/1.0 c 4.0E-07 N/A 2.1 E-05 N/A N/A N/A 2.0E06 D N/A

Chromium a 0.1/1.0 d 4.0E-05 N/A 9.5 E-05 N/A N/A N/A 3.1E-05

D N/A

Cobalt a 1.0 0.0003 N/A N/A N/A N/A N/A 1.63E04 D N/A

Copper a 1.0 4.0E-05 5.6E-04 N/A N/A N/A 3.0E-05 N/A

Lead Compounds 1.0 (organic)

0.1 (inorg.) N/A N/A N/A N/A N/A N/A 1.41E04 D 0.14

~

(organic)

Manganese a 1.0 N/A N/A 2.1E-05 N/A N/A N/A 3.5E-05

D N/A

Mercury a 1.0 0.0006 N/A 4.0E-05 N/A N/A N/A 9.2E-07

D N/AEPCRA Section

313 Chemical **De Minimis**

Level* Crude Oil Gasoline

(Various

Grades) No.2 Fuel

Oil/ Diesel

Fuel Jet Fuel

(JP-4) Kerosene Lubricating

Oil No. 6

Fuel Oil Aviation

Gasoline

Nickel

a 0.1 0.0055 N/A 3.38E-04 N/A N/A N/A 2.6E-03

D N/A

Selenium a 1.0 4.0E-05 N/A N/A N/A N/A N/A 9.5E-06

D N/A

Silver a 1.0 N/A N/A N/A N/A N/A N/A 2.0E-08 N/A

Zinc Compounds 1.0 N/A N/A N/A N/A N/A 1.0 N/A N/A

Unless otherwise noted, Source: Economic Analysis of the Final Rule to Add Certain Industry Groups to EPCRA Se ction 313 , Appendix

B "Composition of Crude Oil and Petroleum Products."

A American P e troleum Institute report prepared for Mr. Jim Durham, EPA (December 23, 1993), regarding revised estimates of heavy

petroleum product liquid cons tituents that are listed as hazardous air pollutants (HAPs) under section 112 of the Clean Air Act

Amendments (CAAA).

R Radian Corporation report prepared for Mr. James Dur ham, EPA (August 10, 1993), regarding liquid HAP concentrations of various

petroleum products.

D Appendix D, Study of Hazardous Air Pollution Emissions from Electric Utility Ste am Generating Units--Final Report to Congress,

USEPA, OAQPS (February 1998) 453/R-98-004b.

T These values have been revised to be consistent with the current version of EPA’s emission estimation program TANKS 4.0.

* The de minimis concentration values for the metals is for the metal compound.

~ Lead compounds concentration for Aviation Gasoline 100 (Exxon-MSDS).

‡ Concentrations updated with comments received from API.

a Constituents are most likely metal compounds rather than the elements. Elements are listed in this table because concentration data

are for only the metals occurring in the fuel . Concentrations for metal compounds would be somewhat higher depending on the metal

compound. For threshold determination, if the weight of the compound is not known, facilities may use the weight of the lowest metal

compound likely to be present.

@ Data from EPA report prepared by Radian Co. for this constituent are considered s uspect and are not recommended for use, based on

discussion with Jim Durham of EPA on November 30, 1998.

b MTBE may be present to enhance octane in concentrations from 0-15% (industry practice, not sampling results).

c The de minimis level for inorganic compounds is 0.1; for organic compounds is 1.0.

d The de minimis level for chromium VI compounds is 0.1; for chromium III compounds is 1.0.

e The petroleum products may contain one or more of the following chemicals under the polycyclic aromatic compounds (PACs) category:

benz(a)anthracene, benzo (b)fluoranthene, benzo (j)fluoranthene, benzo(k)fluoranthene, benzo(rst)pentaphene, benzo(a)phenanthrene,

benzo(a)pyrene, dibenz(a,h)acridine, dibe nz(a,j)acridine, dibenzo(a,h)anthracene, 7H-Dibenzo(c,g)carbazole, dibenzo(a,e)fluoranthene,

dibenzo(a,e)pyrene, dibenzo(a,h)pyrene, dibenzo(a,l)pyr ene, 7,12-dimethylbenz(a)anthracene, indeno[1,2,3-cd]pyrene, 5-methylchrysene,

1-nitropyrene. For No. 6 fuel oil, the value given is for benzo(a)anthracene.

# Appendix C

Hester, C., MACTEC, to S. Shedd, EPA/OAQP S/SPPD. Memorandum on Review of Data on HAP Content in Gasoline. May 18, 2006.TABLE1.SUMMARYOFHAPDATA,WEIGHT%INVAPORHAP1994NESHAPBID1994NESHAPBIDFebruary23,2005CurrentDataFuture(2015)*NormalGasolineOxygenatedGasolineMemo-OTAQdataReviewBenzene0.900.900.740.270.17Cumene0.010.010.010.0120.012Ethylbenzene0.100.100.140.0530.053.N-hexane1.601.601.61.81.8MTBE0.0011.902.42.40?Naphthalene0.050.050.0460.000270.00027Toluene1.301.101.31.41.4Xylene0.500.400.530.560.562,2,4-Trimethylpentane0.800.700.830.750.75Total5.2616.767.67.34.8*Future(2015)assumes:1)BenzenecontentreductioninproposedMSATruleisimplemented,andthatimplementationdoesnotchangetheotherHAPconcentrations.2)MTBEisreplacedasanoxygenatebecauseofgroundwatercontaminationissuesrelatedtoitsuse.

# Appendix D

RTI International. Draft Emission Estimati on Protocol for Petroleum Refineries. For EPA/OAQPS. December 2009.Appendix A—Average Stream CompositionsTable A-1. Refinery Average Stream Hazardous Air Pollutant Compositions—Default ValuesCASNumberHAP ComponentGasolineAlkylateCrude OilReformateNaphthaAvg. Conc. (wt%)Wtd Avg. Conc.(wt%)LiquidVaporLiquidVaporLiquidVaporLiquidVaporLiquidVaporLiquidVaporLiquidVapor106-99-01,3-Butadiene0.00370.0037540-84-12,2,4-Trimethylpentane4.720.95335.49.40.2630.2470.7990.3558.512.292.270.67971-43-2Benzene1.610.6260.1180.0610.4460.8074.613.321.2441.061.611.171.15461.02892-52-4Biphenyl0.010000.0610.000020.0250000.020.0000040.03961.15E-051319-77-3Cresols0.7890.00065000.2180.00080.1410.00020.01910.000030.230.00030.29050.000607498-82-8Cumene0.8490.015650.0040.00010.1260.01080.9680.0330.910.03680.570.020.42580.01638100-41-4Ethylbenzene1.6050.06310.0110.00060.3460.06333.730.2721.3660.1181.410.11.0180.08803110-54-3Hexane7.1384.4283.222.632.467.113.94.487.5310.274.855.784.0456.5511634-04-4Methyl tertiary-butylether3.543.62000000000.710.720.66690.6819891-20-3Naphthalene0.4440.00060.0120.000020.2190.001250.7980.00180.3990.00110.370.0010.33220.001131108-95-2Phenol0.05510.0001000.3230.00310.02760.00010.0660.00030.090.00070.20660.001850100-42-5Styrene3.5280.088200000.09070.0042000.720.020.67370.01703108-88-3Toluene7.210.8420.5030.0770.8780.47714.543.145.051.2955.641.173.8620.88601330-20-7Xylene7.170.2350.02120.00091.420.21613.790.83675.490.3955.580.344.1250.2941Sum of listed HAP38.710.939.312.26.768.9444.012.622.913.530.311.619.110.2

# Appendix E

RTI International. Emission Estimation Protoc ol for Petroleum Refine ries, Version 2.1, ICR Response Version. For OAQ PS/EPA. February 2011.

## Version 2.1 Final ICR Draft Appendix A—Average Stream Compositions

Table A-1. Refinery Average Stream Hazardou s Air Pollutant Compositions—Default Values

Average Weight Percent of Compound in Process Unit Stream a1,3-Butadiene106-99-0n-Hexane110-54-32,2,4-Trimethylpentane540-84-1Benzene71-43-2Toluene108-88-3Xylenes (total)1330-20-7Ethylbenzene100-41-4Cumene98-82-81,2,4-trimethylbenzeneb95-63-6Naphthalene91-20-3Biphenyl92-52-4Styrene100-42-5



### Process Units

Atmospheric Distillation 0.01 4.28 0.05 0.86 1.7 1.97 0.63 0.12 0.63 0.25 0.06 0.001

Vacuum Distillation - 0. 007 0.004 0.004 0.043 0.020 0.024 0.001 0.020 0.12 0.09 - Coking Unit 0.04 2.49 0.75 0.42 1. 30 1.76 0.70 0.12 0.70 0.28 0.001 0.19

Cat Hydrocracker 0.03 1.86 1.04 1.27 2.72 2.67 1.02 0.09 1. 33 0.20 0.001 0.19

FCCU 0.01 0.99 0.29 1.03 3.28 4. 90 1.07 0.10 1.92 0.72 0.43 0.14

CRU 0.009 2.75 0.25 6.34 17.44 17. 61 3.88 0.42 5.93 0.87 0.001 0.11

Hydrodesulfurization - 1.89 0.0001 0.37 1.72 1.94 0.37 0.07 0.40 0.25 0.22 - Alkylation 0.22 1.57 25. 24 0.03 2.05 0.08 5.0E-5 5.0E-5 5.0E-5 5.0E-5 5.0E-5 0.02

Isomerization - 3.22 0.01 0.51 0.64 0.15 - - - - - - Polymerization - 0.54 0.73 1.24 1.76 1.18 0.09 - - - -

Products

Aromatics Extract -

Benzene - - - 99.99 0.009 0.002 - - - - - -

Aromatics Extract -

Toluene - - - 0.296 95.61 3.49 2.82 - 0.3 - - -

Aromatics Extract - Xylenes - - - - - 77.89 16.08 0.59 - - - -

Aromatics Extract - Heavy Aromatics - - - 5.7 19.36 25.03 3.56 0.965 4.94 0.314 - -

Commercial Jet Fuel - 1.68 0.0006 0. 577 0.965 1.22 0.257 0.106 0.815 0.627 0.409 -

Conventional Gasoline 0.0009 2.22 2.94 1.4 c 

### 7.75 6.56 1.490 0.219 3. 002 0.415 - 0.0767

Aviation Gasoline - 2.30 - 1. 01 7.69 3.37 1.2 0. 103 0.5 0.695 - -

Reformulated Gasoline - 1.36 1.10 0.8 c 

### 7 7.31 1.26 0.19 2.52 0.21 - -

Diesel Fuel - 0.030 0.007 0.004 0.081 0.241 0.053 0.056 0.349 0.285 0.117 - Home Heating Oil - - - - 0.108 0.300 0.095 - 0.429 0.453 0.181 -

Solvent-refined Lubes - - - - - - - - - - - -

Crude Oil 9.81E05 

### 1.341 0.185 0.312 0.542 0.811 0.186 0.108 0.377 0.139 0.030

a 

## Based on Petroleum Environmental Re search Forum (PERF) refinery proce ss stream speciation study (API, 2002),

unless otherwise specified.

b 

## 1,2,4-Trimethylbenzene is not a HAP, but it is a prevalent VOC in many refinery streams.

c 

## Average benzene content of conventional and reformulated gasoline based on Fuel Trends Resport: Gasoline

1995-2005 (U.S. EPA. Report No. EPA420-R-08-002. January 2008), corrected to weight percent using the density correction factor of 0.876/0.739 (i.e., 1.16vol%×0.876/0.739 = 1.4wt%; 0.67vol%×0.876/0.739 = 0.8wt%).

# Appendix F

Todd, M., API, to Air and Radiation Docket . Docket ID No. EPA-HQ-OAR-2010-0600, Letter with Comments on EPA’s Proposed Rule – Resi dual Risk and Technology Review (RTR) for

National Emission Standards for Marine Tank Ve ssel Loading Operations. Docket item no. EPA-HQ-OAR-2010-0600-0359. Dated December 6, 2010.

## ATTACHMENT 2

– HAP Emissions per Million Gallons of Gasoline Loaded

The estimated HAP emissions per million barrels per year (M bbl/yr) of gasoline loaded depends upon the assumed concentration of volatile organic compound (VOC) vapors in the air/vapor mixture displaced from the cargo compartments, and the concentration of HAP constituents in that vapor.

VOC emission factors . Emission factors for the loading of gasoline at marine terminals are given in Table

5.2- 2 of EPA’s AP -42 document. These values range from 0.7 pounds of VOCs per thousand gallons loaded
(lbs/10 3 

## gal) to 3.9 lbs/10 3 

## gal, depending upon the size of the vessel and the prior condition of the cargo compartment. The value that would result in the highest emissions estimate, then, would be 3.9 lbs/10 3 

## gal.

HAP content . EPA recommends, in paragraph 7.1.4 of AP-42, the application of Raou lt’s Law to determine
the HAP content in the vapor phase of a hydrocarbon mixture from the HAP content in the liquid phase of that mixture. Typical HAP concentrations in the liquid phase of normal gasoline may be obtained from EPA’s TANKS software program (similar concentrations are given in EPA’s EPCRA Section 313 Industry

Guidance, Petroleum Terminals and Bulk Storage Facilities , EPA 745-B-00-002, February 2000). The use of MTBE in motor gasoline has been phased out in the United States, and thus the concentration of MTBE should be given as 0%. Using typical values for the properties of gasoline and a temperature of 60 o 

## F, the determination of vapor phase concentrations by Raoult’s Law is illustrated in the following table:

RVP Ml A B Pva (psia) Mv



## Gasoline 10 92 11.724 5237.273 5.19 66

temp(F) 

### 60 Yi ( Mi / Mvt )

liquid liquid phase liquid 

### temp(C) 

### 15.6 vapor partial vapor 

### HAP/VOC

p hase molecular wt. phase pressure pressure phase vapor phase



## Wi Mi Xi Antoine's Constants (de g.C) Pi* Pi Yi Zi

Species: {wt percent } {lb/lb

- mole} {mole frac.} 

## A B C vapor pressure {psia} {mole frac.} {wt percent}



## n

- hexane 1.0% 86.18 0.011 6.878 1171.5 224.37 1.9126 0.0204 0.0039 0.51%

benzene 1.8% 78.11 0.021 6.906 1211 220.79 1.1709 0.0248 0.0 048 0.57%

iso

- octane 4.0% 114.23 0.032 6.812 1257.8 220.74 0.5962 0.0192 0.0037 0.64%

toluene 7.0% 92.14 0.070 7.017 1377.6 222.64 0.3311 0.0231 0.0045 0.62%

ethylbenzene 1.4% 106.17 0.012 6.95 0 1419.3 212.61 0.1037 0.0013 0.0002 0.04%

xylene (

- m) 7.0% 106.17 0.061 7.009 1462.3 215.11 0.0903 0.0055 0.0011 0.17%

cumene 0.5% 120.19 0.004 6.929 1455.8 207.2 0 0.0479 0.0002 0.0000 0.01%

MTBE 0.0% 88.15 0 6.872 1116.8 224.74 3.2415 0.0000 0.0000 0.00%

naphthalene 0.0% 128.17 0 7.146 1831.6 211.82 0.0024 0. 0000 0.0000 0.00%

22.7 % = sum of HAP in the liquid sum of HAP in the vapor = 2.56%

This analysis is conservative, in that it uses a benzene concentration of 1.8%, whereas actual benzene concentrations in gasoline in the United States has been driven down to the range of 0.5- 0.6% by EPA’s
Fuels Specifications. Nevertheless, the HAP concentration in the vapor phase will be rounded up to 3% for purposes of this illustration.