July 15, 2010

1 ESTIMATION OF MACT ALLOWABLE EMISSION LEVELS AND ASSOCIATED RISKS

AND IMPACTS FOR THE RTR GROUP 2A SOURCE CATEGORIES

The purpose of this document is to present analyses related to “MACT allowable ” emissions

levels for four source categories covered by the Group 1 Polymers and Resins NESHAP (Polymers and Resins I NESHAP) that are being addressed under EPA’s Risk and Technology Review (RTR)

program. This program is addressing the statutory requirements in section 112(f) and 112(d)(6) of the

Clean Air Ac t for federal air toxics regulations. The regulations are National Emission Standards for Hazardous Air Pollutants (NESHAP) contained in 40 CFR part 63. They are commonly referred to as

Maximum Achievable Control Technology ( MACT ) standards. The emissio ns data being used for the RTR risk assessments for these categories consists of data representative of “actual” emission levels. In addition to the risks associated with these actual emission levels, EPA also considers the

levels of HAP emissions that so urces could emit and still be in compliance with the applicable MACT regulation. T hese emission levels are referred to as “ MACT allowable” emissions. The purpose of

this memorandum is to discuss these MACT allowable emission levels and their impact on th e baseline risks.

The Polymers and Resins I addresses nine source categories, four of which are included in this

memorandum: Epichlorohydrin Elastomers Production, Nitrile Butadiene Rubber Production, and Styrene Butadiene Rubber and Latex Production.

This memorandum is organized as follows. Section 1 presents the estimated maximum risk

levels based on the actual emission levels for all four source categories , and Section 2 discusses the basic approach to estimating the risks from the MACT allowable l evels . This is followed by a discussion of the estimation of MACT allowable emission level, particularly as it relates to the actual

emission levels used in the risk assessments. This is followed by a presentation of the estimated risks

at these MACT all owable levels.

1.0 Risk Levels Based on Actual Emissions

The estimated maximum inhalation risks for these five source categories are summarized in

Table 1

. These risks are based on actual emission levels.July 15, 2010

2 Table 1 . Summary of Estimated Inhalation Risks for the Five Polymers and Resins I Source Categories Based On Actual Emissions Levels

Source Category Maximum individual cancer risk (in a million) 1 Maximum chronic

noncancer TOSHI 2

Epichlorohydrin Elastomers Production 1 0 0. 1

Nitrile Butadiene Rubber Production 2 0. 00 9

Polybutadiene Rubber Production 30 0. 3

Styrene Butadiene Rubber and Latex Production 10 0.2

1 Maximum individual excess lifetime cancer risk.

2 Maximum target organ specific hazard index (TOSHI). Target organ system represented by t he TOSHI varies across source categories. Maximum TOSHI is respiratory for epichlo rohydrin elastomers production. Maximum TOSHI for

nitrile butadiene rubber production, polybutadiene rubber production, and styrene butadiene rubber and latex production is based on reproductive effects.

2.0 Basic Approach to Estimating Risks from MACT Allowable Emission Levels

Detailed emission point

- specific MACT allowable emissions information is not available. Therefore, modeling was not conducted to estimate the r isks from MACT allowable emission levels.

T he basic approach to estimate the risks from MACT allowable emission levels was to first estimate the relationship between the actual and MACT allowable emission levels, and then to estimate the potential risk i mpacts f rom the differences between actual and MACT allowable emissions. In general, the risk impact was assumed to be proportional to the difference in emission levels. For example, if MACT allowable emissions were estimated to be three times as high as actual emissions, it was assumed that risks could be as much as three times as high as those estimated from

the modeling conducted using actual emissions.

This assumption regarding the linear relationship between emissions a nd risks is generally

reasona ble for chronic cancer and noncancer risks. However, using this approach for acute risks would likely overestimate the impacts. The acute assessment already has built in nu merous conservative assumptions. First, the acute assessment assume d a short

- term emission rate up to 10 times that of the average longer term emission rate. Also, t he maximum acute risks assume the simultaneous occurrence of independent factors that may vary greatly, such as hourly emissions rates, meteorology, and human activity pat terns. In th e assessment using actual emissions

, EPA assume d

that individuals remain ed for 1 hour at the point of maximum ambient concentration as determined by

the co

- occurrence of peak emissions and worst

- case meteorological conditions. These assumptio ns would tend to overestimate actual exposures since it is unlikely that a person would be located at the point of maximum exposure during the time of worst

- case impact. The addition of another factor to

account for MACT allowable emissions level further increases the conservativeness of the estimated

MACT allowable acute risks. Therefore, this analysis does not estimate acute risks for the MACT

allowable emissions level.July 15, 2010

3 3.0 Results of Analysis

The Gr oup 1 Polymers and Resins NESHAP addresses emission s from the following types of

emission sources for all four source categories: (1) storage tanks, (2) front

- end process vents, (3)

back

- end process operations, (4) equipment leaks, and ( 5 ) wastewater. The process “front

- end” includes pre

- polymerization, reaction, stripping, an d material recovery operations. In addition, the

NESHAP addresses emissions from back

- end process operations for the Polybutadiene and Styrene

Butadiene Rubber and Latex source categories, where the process “back

- end” includes all o perations after stripping (predominately drying and finishing) . Table 2 summarizes the formats of the standards for these emission points.

Table 2

. Formats of Standards for Group 1 Polymers and Resins I NESHAP

Emission Source Type Format of Primary Sta ndard Storage Tanks Equipment Standards

Front

- End Process Vents Performance Standard (% reduction)

Back

- End Process (only for Polybutadiene and Styrene Butadiene Rubber) Emission Limit (kg emissions/Mg latex or crumb rubber) Equipment Leaks Work Practi ce Standards

Wastewater Equipment Standards , Performance Standard

The ability to estimate MACT allowable emissions for specific emission points, or for specific emission point types, is largely dependent o n the format of the standards. For equipment s tandards, sources subject to the regulation are required to install specific equipment

. A ssuming that the equipment is maintained properly and is in good working condition (as required), there would not be a

difference in the actual emissions level and th e level allowed by the standard. Similarly, there would

be no difference between actual and MACT allowable emissions for emission sources subject to work practice requirements , provided that facilities are not conducting additional work practices proven t o reduce emissions beyond those required in the rule. We are not aware of any such situations at facilities in these five Group 1 Polymers and Resins source categories. Therefore, for equipment leaks and storage vessels, which are subject to equipment an d work practice standards, we believe that

the actual emission levels are a reasonable estimation of the l evels allowed by the standard.

For wastewater emission sources, the regulation includes an assortment of equipment and performance standards. As di scussed above, it is reasonable to assume that the actual emissions from those sources subject to equipment standards are representative of the MACT allowable emissions. In general, it is possible that sources could overcontrol sources subject to a perfor mance standard. This would result in the actual emissions being lower than the MACT allowable emissions. However, for wastewater sources, we are not aware of any such overcontrol. Therefore, we believe that the actual

wastewater emission levels are a re asonable estimation of the levels allowed by the standard.

For front

- end process vents, which are subject to a performance standard, we believe that there are situations where sources are utilizing control devices that achieve reductions greater than the required 98 percent reduction. However, the continuous monitoring requirements of the rule result in

situation s where reductions greater than 98 percent are required on a continuous basis

. Specifically, owners and operators are required to conduct perfo rmance tests to demonstrate initial compliance. During the test, they are required to monitor a specific parameter (e.g., temperature for a thermal incinerator) . From the data collected during the test, they are required to calculate a parameter levelJuly 15, 2010

4 (e .g., a minimum temperature) that is indicative of the control device performance achieved during

the test. Ongoing compliance is then determined based on the continuou s monitoring of this

parameter as compared to the established level (e.g., if the incine rator temperature falls below the minimum temperature established during the test it would be an excursion) . Therefore, if an incinerator was achieving a 99 percent emission reduction during the performance test, the temperature level established based on monitoring data collected during the test would be reflective of a 99 percent reduction. Thus, the performance level required by the rule would, in effect, be 99 percent. Because of these requirements, we assume that the actual emission levels are a rea sonable

estimation of MACT allowable emissions for front

- end process vents.

Since there are no standards applicable to the back

- end process emissions from Epichlorohydrin, and Nitrile Butadiene Rubber, the MACT allowable and actual emissions are equivale nt. As shown in Table 2 , t he format of standards for emissions from back

- end process operations at plants in the P olybutadiene R ubber Production and S tyrene B utadiene R ubber and Latex production is an emission limitation based on production

. The units of the standard for P olybutadiene

R ubber Production are kilograms HAP emissions allowed per Megagram of crumb rubber product.

C rumb rubber is the final product of this process, so MACT allowable emissions can be estimated using production data. Since actua l production data are confidential business information, an estimate of production was determined using published “name plate ” capacities. The result of this calculation

is that MACT allowable emissions are approximately 10

, 6 00 tons/year, which is approxim ately seven times higher than the actual emissions of around 1,600 tons/yr for the plants in the P olybutadiene

R ubber P roduction source category

. Details of this calculation are provided in Attachment 1.

The units of the back

- end process operations stan dard for the S tyrene B utadiene R ubber and

Latex Production source category are kilograms HAP emissions allowed per Megagram of latex. Facilities subject to this standard utilize an emulsion process, where the reaction occurs in a water

based solution form ing a latex. Following the formation of this latex, steam is injected into the latex which results in the coagulation of solid rubber crumb, which is the final product. It should be noted that there are nine major source facilities in the data set for th e Styrene Butadiene Rubber and Latex Production source category. However, only three of these facilities produce rubber. At the six other facilities, the final product is styrene butadiene latex. Therefore, they do not produce a solid product

and do not have back

- end processes. While an estimate of the amount of final crumb product can be

obtained from “ nameplate ” capacities, an additional assumption regarding the relative weight of the crumb in the latex is required. The result of this calculation is that MACT allowable emissions are approximately 1,100 tons/yr, which is around five times higher than the actual emissions of approximately 2 4 0 t ons/yr from the s tyrene butadiene rubber production facilities in the source

category that are subject to this emission limitation

. Details of this calculation are also provided in

Attachment 1.

Table 3 summarizes the ratios of MACT allowable to actual emissions for the five Group 1 Polymers and Resins source categories. As discussed above and summarized in Tab le 3, the only emission point type where the MACT allowable emissions levels are different from the actual

emissions levels are the back

- end process emissions from the Polybutadiene Rubber and Styrene Butadiene Rubber and Latex source categories. Table 4 shows the overall back

- end emission levels

for the se two source categories. Overall for the emissions from all sources from the category , the

MACT allowable emissions from the Polybutadiene Rubber source category are seven times as high

as the actual emis sions. This ratio is four for the Styrene Butadiene Rubber and Latex source

category.July 15, 2010

5 Table 3 . Summary of MACT Allowable to Actual Emission Ratios for Group 1 Polymers and Resins Source Categories

Source Category Ratio of MACT Allowable Emissions to A ctual Emissions

Storage

Vessels Front

- End

Process

Vents Back

- End

Process Operations Equipment

Leaks Wastewater

Epichlorohydrin 1:1 1:1 1:1 1:1 1:1

Nitrile Butadiene

Rubber 1:1 1:1 1:1 1:1 1:1

Polybutadiene

Rubber 1:1 1:1 7 :1 1:1 1:1

Styrene Butadiene

Rubber and Latex 1:1 1:1 5:1 1:1 1:1

Table 4 . Summary of MACT Allowable to Actual Emission Emissions for Polybutadiene Rubber and Styrene Butadiene Rubber and Latex

Emission Source Type HAP Emissions (tons/yr)

Actual MACT Allowable Polybutadiene R ubber

B ack

- end process vent 1,594 10,593 Styrene Butadiene Rubber and Latex

B ack

- end process vent 237 1,140

The risk assessment conducted for these categories in 2010 did not explicitly estimate risks from individual emission sources types. Howeve r, it did identify the sources that contribute at least

90 percent of the maximum risk. Using this information on the risk driver emission sources, estimates were made of the upper bound impact the higher MACT

- allowable back

- end emissions

levels could hav e on the maximum risks. Following is an example of this methodology.

The maximum cancer risk from a hypothetical polybutadiene rubber production facility was 8.2 in 1 million, a

a Note: Risks are only reported to one significant figure. However, this calculation was conducted with raw risk numbers

be fore this rounding. which would be reported at 8 in 1 million. Assume HAP emissions from a fron t

- end process vent contributed 85 percent of this risk and HAP emissions from a storage tank contributed

10 percent. Therefore, the sources contributing 95 percent of this maximum cancer risk, or 7.8 in 1 million, were known

. Since the ratio of MACT

- allo wable to actual emissions for these source types was 1:1, this would represent the MACT

- allowable risk from these sources. While the contribution

from back

- end process emissions was not explicitly reported, the upper bound contribution of the back end pro cess emissions would be 5 percent of this maximum cancer risk based on actual

emissions , or 0.4 in 1 million . A factor was appli ed to account for the fact that some HAP emitted

from the back

- end process operations are not carcinogens (i.e., do not have a unit risk estimate) and

would not contribute to the estimated cancer risks. The mass percentage of carcinogens to noncarcinogens was applied to the upper bound risk contribution to estimate the potential contribution

to the maximum cancer risk based on ac tual emissions. Assuming that the only 30 percent of theJuly 15, 2010

6 back

- end emissions, by mass, were of carcinogenic HAP, the potential risk from the back end would

be 0.12 in 1 million. Applying the 7:1 factor would indicate that the MACT

- allowable cancer risk

fr om back

- end process emissions is 0.8 in 1 million. Adding this risk to the 8.2 in 1 million MACT

allowable risk from the front

- end vents and storage tanks, the upper bound maximum cancer risk at

the MACT

- allowable level would be 9 in 1 million

.

Table 5 shows the facility

- specific comparison of maximum risks based on both actual and

MACT

- allowable emission levels for the Polybutadiene and Styrene Butadiene Rubber and Latex source categories. As can be seen from Table 5, the maximum risks for both catego ries are the same

at both the actual and MACT

- allowable emission levels. Appendix B provides details of these

estimates.

Table 5. Facility

- Specific Maximum Risks Based on MACT Allowable and Actual Emission

Levels for Polybutadiene Rubber and Styrene But adiene Rubber and Latex

Facility ID Maximum individual cancer risk (in a million) Maximum chronic noncancer

TOSHI

Actual

Emissions MACT

Allowable

Emissions Actual

Emissions MACT

Allowable

Emissions
Polybutadiene Rubber Production

NEI32876 3 3 0.05 0.05

NEI33012 0.5 0.5 0.01 0.01

NEI7039 10 10 0.2 0.2

NEI7446 20 20 0.3 0.3

NEI8307 9 9 0.2 0.2 Styrene Butadiene Rubber and Latex Production

NEI13230 7 7 0.1 0.1

NEI33015 3 3 0.1 0.1

NEI8360 10 10 0.2 0.2 Note: The source category maximu m risk from the polybutadiene source category is 30 due to the close proximately of

facilities

Following are the conclusions fr o m this analysis:

**•** The only emission point where there is an appreciable difference in emissions at the actual

level and the M ACT allowable level is back

- end process operations for the Polybutadiene Rubber and Styrene Butadiene Rubber and Latex source categories.

**•** The maximum risks based on actual emission levels from the Polybutadiene Rubber and Styrene Butadiene Rubber and La tex source categories are based on emissions from sources

other than the back

- end process operations.

**•** The overall conclusion is that the maximum risks for the five Polymers and Resins source categories are the same for both the actual emissions level and the MACT

allowable emissions level.July 15, 2010

1 ATTACHMENT A. ESTIMATION OF GROUP 1 POLYMERS AND RESINS

BACK

- END PROCESS MACT ALLOWABLE EMISSIONS

Table A

- 1. Estimation of MACT Allowable Back

- End Emissions for Polybutadiene Rubber

Facility “NamePlate” Capacity 1

(Mg/yr) Actual

Production Capacity 2

(Mg/yr) MACT

Allowable

HAP

Emissions 3

(kg/yr) MACT

Allowable

HAP

Emissions (tons/yr) Actual HAP

Emissions (tons/yr)

AMERICAN SYNTHETIC RUBBER 180,000 162,000 1,620,000 1,782 362

LANXESS 180,000 162,000 1,620,000 1,782 93

FIRESTONE POLYMERS/ORANGE TX 145,000 130,500 1,305,000 1,436 70

FIRESTONE POLYMERS/LAKE CHARLES LA 180,000 162,000 1,620,000 1,782 685

GOODYEAR 385,000 346,500 3,465,000 3,812 384

Totals 10,593 1,594

1 Worldwide Rubber Statistics 2007. Internatio nal Institute of Synthetic Rubber Producers, Inc.

2 Adjusted to 90% of Nameplate Capacity to account for down times for maintenance shutdowns, product changeouts, etc.

3 Calculated using the emission standard of 10 kg total organic HAP allowed per Mg of crumb rubber produced.

Table A

- 2 . Estimation of MACT Allowable Back

- End Emissions for Styrene Butadiene Rubber

Facility “NamePlate” Capacity 1

(Mg/yr) Actual

Production Capacity 2

(Mg/yr) MACT

Allowable

HAP

Emissions 3

(kg/yr) MACT

Allowable

HAP

Emissions (tons/yr) Actual HAP

Emissions (tons/yr)

GOODYEAR HOUSTON CHEM PLT 300,000 270,000 432,000 475 153

DSM COPOLYMER/BR PLANT 150,000 135,000 216,000 238 9

ISP ELASTOMER 270,000 243,000 388,800 428 75

Totals 1,140 237

1 Worldwide Rubber Statistics 2007. International Institute of Synthetic Rubber Producers, Inc.

2 Adjusted to 90% of Nameplate Capacity to account for down times for maintenance shutdowns, product changeouts, etc.

3 Calculated using the emission standard of 0.4 kg total organic HAP allow ed per Mg of latex produced and assuming that the crumb rubber makes up 25 percent of the latex by weight

. 

# ( **) (**  **)**

oduction Mg HAP kg yr Mg pacity oductionCa Actual yr kg Emissions AP AllowableH Pr 4

. 0

% 25 ) / ( Pr * ) / ( **=**Table B-1. Estimation of MACT-Allowable Cancer RisksEmissionSource IDType of EmissionSourceHAPCancer Riskfrom HAP andSourceContribution toMaximum CancerRisk (%)SB1_NEI8360 9.89E-06 10 SB101014 Eq Leaks 1,3-Butadiene 8.15E-06 82.3 3.7 3.66E-07 5.5% 2.02E-08 1.01E-07 9.97E-06 10SB101013 Wastewater 1,3-Butadiene 1.38E-06 14.0SB1_NEI13230 7.05E-06 7 SB101200 Eq Leaks 1,3-Butadiene 2.51E-06 35.7 8.4 5.93E-07 0.4% 2.37E-09 1.18E-08 7.06E-06 7SB102102 Front-End 1,3-Butadiene 1.07E-06 15.3SB101182 Eq Leaks 1,3-Butadiene 6.60E-07 9.4SB101199 Eq Leaks 1,3-Butadiene 6.29E-07 8.9SB101202 Eq Leaks 1,3-Butadiene 5.05E-07 7.2SB101215 Wastewater 1,3-Butadiene 4.15E-07 5.9SB101181 Eq Leaks 1,3-Butadiene 2.41E-07 3.4SB101206 Wastewater 1,3-Butadiene 2.14E-07 3.0SB101214 Wastewater 1,3-Butadiene 2.03E-07 2.9SB1_NEI330153.42E-06 3SB101003 Eq Leaks1,3-Butadiene3.37E-06 98.5 1.5 5.16E-08 2.3% 1.21E-09 6.04E-09 3.42E-06 3PB1_NEI74461.78E-05 20PB102036 Storage Tank 1,3-Butadiene 1.66E-05 93.1 6.9 1.23E-06 0.0% 0.00E+00 0.00E+00 1.78E-05 20PB1_NEI70391.19E-05 10PB101033 Eq Leaks 1,3-Butadiene 2.99E-06 25.2 9.7 1.15E-06 5.5% 6.38E-08 4.46E-07 1.22E-05 10PB101036 Wastewater 1,3-Butadiene 2.27E-06 19.2PB101065 Wastewater 1,3-Butadiene 1.82E-06 15.4PB101004 Eq Leaks 1,3-Butadiene 1.75E-06 14.7PB102034 Front-end 1,3-Butadiene 1.17E-06 9.9PB102063 Front-End 1,3-Butadiene 7.04E-07 5.9PB1_NEI83079.09E-06 9PB101006 Eq Leaks 1,3-Butadiene 8.49E-06 93.4 6.6 5.98E-07 0.3% 1.66E-09 1.16E-08 9.10E-06 9PB1_NEI328762.98E-06 3PB101001 Eq Leaks 1,3-Butadiene 2.68E-06 90.1 9.9 2.94E-07 0.0% 0.00E+00 0.00E+00 2.98E-06 3PB1_NEI330125.24E-07 0.5PB101001 Eq Leaks 1,3-Butadiene 4.06E-07 77.4 22.6 1.18E-07 0.1% 1.04E-10 7.26E-10 5.25E-07 0.5PB102003 Back-End 1,3-Butadiene6.97E-08 13.3Potential MaximumCancer Risk FromFacility (MACTAllowable Emissions)Styrene-Butadiene Rubberand LatexSource CategoryPolybutadiene RubberReported RiskValue in 1million (ActualEmissions)Reported RiskValue in 1 million(AlowableEmissions)Potential CancerRisk From BackEnd (ActualEmissions)Mass percentageof Back-EndEmissions that areCarcinogensDriver Emission Sources and Related RisksMaximumCancer Riskfor Facility(ActualEmissions)Facility IDPotential Cancer RiskFrom Back-End(MACT-AllowableEmissions)Upper BoundPotential Cancer RiskFrom Back-End(Actual Emissions)Max Risk % NotAttributable toDriversTable B-2. Back-End Emissions SummaryPolybutadiene RubberstrNTISiteID HAP Carcinogen? Total Carcinogens% Back-EndCarcinogenEmissionsNEI32876 Styrene 23.6Toluene 338.8Total 362.4 0.0 0.0%NEI33012 1,3-Butadiene Y 0.6 0.6Hexane 684.7Styrene 0.0Total 685.3 0.6 0.1%NEI7039 Ethyl Benzene Y 21.3 21.3Hexane 330.3Styrene 32.3Total 383.9 21.3 5.5%NEI7446 Hexane 91.9Toluene 0.8Total 92.8 0.0 0.0%NEI8307 1,3-Butadiene Y 0.2 0.2Hexane 69.0Styrene 0.9Total 70.1 0.2 0.3%Styrene Butadiene RubberstrNTISiteID hap Carcinogen? Total Carcinogens% Back-EndCarcinogenEmissionsNEI13230 1,3-Butadiene Y 0.0 0.0Carbon Disulfide 3.1Ethyl Benzene Y 0.6 0.6Styrene 148.0Toluene 0.3Xylenes (Mixture of o, m, and p Isomers) 0.6Total 152.5 0.6 0.4%NEI33015 1,3-Butadiene Y 0.2 0.2Styrene 8.4Total 8.6 0.2 2.3%NEI8360 Benzene Y 0.7 0.7Ethyl Benzene Y 3.5 3.5Styrene 66.8Toluene 0.5Xylenes (Mixture of o, m, and p Isomers) 3.5Total 74.8 4.1 5.5%Emissions (tpy)Emissions (tpy)Table B-3. Estimation of MACT-Allowable Noncancer RisksEmissionSource IDType ofEmissionSourceHAPHazard Indexfrom HAP andSourceContribution toMaximum CancerRisk (%)SB1_NEI8360 0.2 SB101014Eq Leaks1,3-Butadiene 0.136 84% 0% 0.0 0.0000 0.2SB101013 Wastewater 1,3-Butadiene 0.023 14%SB102012 Front End 1,3-Butadiene 0.002 2%SB1_NEI13230 0.1 SB101200Eq Leaks1,3-Butadiene 0.042 36% 8% 0.00009 0.0005 0.1SB102102 Front End 1,3-Butadiene 0.018 15%SB101182Eq Leaks1,3-Butadiene 0.011 9%SB101199Eq Leaks1,3-Butadiene 0.010 9%SB101202Eq Leaks1,3-Butadiene 0.008 7%SB101215 Wastewater 1,3-Butadiene 0.007 6%SB101181Eq Leaks1,3-Butadiene 0.004 3%SB101206 Wastewater 1,3-Butadiene 0.004 3%SB101214 Wastewater 1,3-Butadiene 0.003 3%SB1_NEI33015 0.1 SB101003Eq Leaks1,3-Butadiene 0.056 98% 2% 0.00001 0.00004 0.1SB102005Back End1,3-Butadiene 0.001 2%PB1_NEI7446 0.3 PB102036 Storage 1,3-Butadiene 0.28 93% 7% 0.00020 0.0014 0.3PB1_NEI7039 0.2 PB101033 Eq Leaks 1,3-Butadiene 0.05 26% 6% 0.00011 0.0008 0.2PB101036 Wastewater 1,3-Butadiene 0.04 20%PB101065 Wastewater 1,3-Butadiene 0.03 16%PB101004 Eq Leaks 1,3-Butadiene 0.03 15%PB102034 Front End 1,3-Butadiene 0.02 10%PB102063 Front End 1,3-Butadiene 0.01 6%PB1_NEI8307 0.2 PB101006 Eq Leaks 1,3-Butadiene 0.14 93% 7% 0.00010 0.0007 0.2PB1_NEI32876 0.05 PB101001 Eq Leaks 1,3-Butadiene 0.04 90% 10% 0.00005 0.0003 0.05PB1_NEI33012 0.01 PB101001 Eq Leaks 1,3-Butadiene 0.01 77% 23% 0.00002 0.0001 0.01PB102003 Back End 1,3-Butadiene 0.00 13%Polybutadiene RubberUpper Bound PotentialHazard Index FromBack-End (ActualEmissions)Upper Bound PotentialHazard Index from Back-End(MACT-AllowableEmissions)Upper Bound PotentialMaximum Hazard IndexAllowable Emissions)Styrene ButadieneRubber and LatexSource Category Facility IDMaximumHazard Index(ActualEmissions)Driver Emission Sources and Related RisksMax Risk % NotAttributable toDrivers