Appendix 1 

Emissions Inventory Support Memorandum 
Polymers and Resins I 
1

MEMORANDUM 

TO: Anne Pope, EPA 

FROM: Darcy Wilson, ERG 

DATE: July 19, 2010 

SUBJECT: Emissions Data Used in Residual Risk Modeling: Polymers and Resins I 

The purpose of this memorandum is to provide information on the RTR database used in 

estimating residual risk for four Polymers and Resins I Maximum Achievable Control 

Technology (MACT) source categories—Epichlorohydrin Elastomers Production, Nitrile 

Butadiene Rubber Production, Polybutadiene Rubber Production, and Styrene Butadiene 

Rubber and Latex Production. 

BACKGROUND 

Section 112 of the Clean Air Act (CAA) establishes a two-stage regulatory process to 

address emissions of hazardous air pollutants (HAPs) from stationary sources. In the first 

stage, section 112(d) requires the Environmental Protection Agency (EPA) to develop 

technology-based standards for categories of industrial sources. In the second stage, 

known as the residual risk stage, section 112(f)(2) requires EPA to assess the health and 

environmental risks that remain after sources come into compliance with MACT. If 

additional risk reductions are necessary to protect public health with an ample margin of 

safety or to prevent adverse environmental effects, EPA must develop standards to 

address these remaining risks. As part of this second stage, data were gathered to assess 

the residual risks from the four Polymers and Resins I MACT source categories. 

EMISSIONS DATA USED IN RESIDUAL RISK MODELING 

Information collected from industry served as the starting point for these assessments. 

This information was also incorporated into the 2002 National Emissions Inventory 

(NEI) by assigning the emissions estimates to the specific process MACT codes1 within 

the NEI (1311, 1321, 1325, and 1339). The 2002 NEI data for Polymers and Resins I 

were released through an Advanced Notice of Proposed Rulemaking (ANPRM) in March 

of 2007, where NEI revisions for facilities in the MACT source categories were solicited 

from State and local agencies, industry representatives, and EPA. The revisions that were 

provided to EPA were incorporated into the 2005 NEI prior to the initial NATA 

modeling. 

 

 

1

 Assigning data with MACT codes allows EPA to determine reductions attributable to the MACT 

program. The NEI associates MACT codes corresponding to MACT source categories with stationary 

major and area source data. 
2

Epichlorohydrin Elastomers Production 

Risks associated with the facility covered by the Epichlorohydrin Elastomers Production 

MACT standard were modeled in the initial 2005 NATA risk assessment in June of 2009. 

EPA reviewed the results of this analysis, and performed an in-depth review of the NEI 

data set for the source category. EPA also incorporated information received in response 

to an industry Information Collection Request (ICR), and evaluated the facility-wide risks 

for Epichlorohydrin Elastomers Production using the 2005 NEI data and risk assessment 

results that were released in the 2005 NATA Risk Preview with State and local agencies 

in June of 2010. Revisions were made to the emissions estimates for the facility based on 

these analyses and updated information. These revisions were included in the risk 

analyses, and will be reflected in the final NATA risk assessment. 

Nitrile Butadiene Rubber Production 

Risks associated with the facility covered by the Nitrile Butadiene Rubber Production 

MACT standard were modeled in the initial 2005 NATA risk assessment in June of 2009. 

EPA reviewed the results of this analysis, and performed an in-depth review of the NEI 

data set for the source category. EPA also incorporated information received in response 

to an industry ICR, and evaluated the facility-wide risks for Nitrile Butadiene Rubber 

Production using the 2005 NEI data and risk assessment results that were released in the 

2005 NATA Risk Preview with State and local agencies in June of 2010. Revisions were 

made to the locational coordinates and emissions estimates for the facility based on these 

analyses and updated information, and closed facilities, minor sources, and sources that 

no longer manufacture nitrile butadiene rubber were identified. These revisions were 

included in the risk analyses, and will be reflected in the final NATA risk assessment. 

Polybutadiene Rubber Production 

Risks associated with facilities covered by the Polybutadiene Rubber Production MACT 

standard were modeled in the initial 2005 NATA risk assessment in June of 2009. EPA 

reviewed the results of this analysis, and performed an in-depth review of the NEI data 

set for the source category. EPA also evaluated the facility-wide risks for Polybutadiene 

Rubber Production using the 2005 NEI data and risk assessment results that were 

released in the 2005 NATA Risk Preview with State and local agencies in June of 2010. 

Revisions were made to the emissions estimates for one facility based on these analyses. 

These revisions were included in the risk analyses, and will be reflected in the final 

NATA risk assessment. 

Styrene Butadiene Rubber and Latex Production 

Risks associated with facilities covered by the Styrene Butadiene Rubber and Latex 

Production MACT standard were modeled in the initial 2005 NATA risk assessment in 

June of 2009. EPA reviewed the results of this analysis, and performed an in-depth 

review of the NEI data set for the source category. EPA also evaluated the facility-wide 

risks for Styrene Butadiene Rubber and Latex Production using the 2005 NEI data and 
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risk assessment results that were released in the 2005 NATA Risk Preview with State and 

local agencies in June of 2010. Revisions made based on these analyses consisted of 

identification of closed facilities. These revisions were included in the risk analyses, and 

will be reflected in the final NATA risk assessment.