Appendix 1 Emissions Inventory Support MemorandumSteel Pickling1 MEMORANDUM

TO: Anne Pope, EPA

FROM: Darcy Wilson, ERG

DATE: July 15, 2010

SUBJECT: Emissions Data Used in Residual Risk Modeling for Steel Pickling

The purpose of this memorandum is to provide information on the RTR database used in estimating residual risk for the Steel Pick ling Maximum Achievable Control Technology (MACT) source category.

BACKGROUND

Section 112 of the Clean Air Act (CAA) establ ishes a two-stage regu latory process to address emissions of hazardous air pollutants ( HAPs) from stationary sources. In the first stage, section 112(d) requires the Environmental Protecti on Agency (EPA) to develop technology-based standards for categories of industrial sour ces. In the second stage, known as the residual risk stage, section 112( f)(2) requires EPA to a ssess the health and

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

additional risk reductions are ne cessary to protect public health with an ample margin of safety or to prevent adverse environmenta l 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 Steel Pickling MACT source category.

EMISSIONS DATA USED IN RESIDUAL RISK MODELING

The 2005 National Emissions Inventory (NEI) data that were modeled in the EPA’s

initial 2005 National Air Toxics Assessment (NATA) risk assessment in June of 2009 served as the starting point for this a ssessment. Using the process MACT code, 1 a subset of the NEI was developed that contained faci lity, process, and emissions data for each facility in the Steel Pickling s ource category (MACT code 0310).

After initial 2005 NATA modeling, EPA evalua ted the 2005 NEI to see if missing Steel Pickling facilities could be identified and adde d to the NEI, if any revisions were needed for facilities in the NEI, and if any facilitie s were identified erroneously as Steel Picking facilities, or facilities have closed. To iden tify additional facilities, EPA reviewed the AIST 2009 Directory of Iron and Steel Plants . The AIST directory also helped EPA revise MACT code assignments to identify addi tional facilities as Steel Pickling facilities that were already included in the NEI. Faci lities that were erroneously identified as having Steel Pickling operations were identi fied based on contacts with facilities to

1 Assigning data with MACT codes allows EPA to determine reductions attributable to the MACT program. The NEI associates MACT codes corresp onding to MACT source categories with stationary major and area source data.2 discuss their operations (e.g., they are not s ubject to the Steel Pickling NESHAP because they don’t do steel pickling).

Emissions data for high-risk facilities iden tified in the initial NATA modeling were reviewed and compared against several year s of Toxic Release I nventory (TRI) data and State inventory data. Se veral facilities were contacted to confirm (or correct) emission values. In addition to revising emi ssion estimates based on this analysis, the following types of revisions were also made to improve the 2005 NEI for Steel Pickling

facilities: revised Source Cl assification Codes (SCCs) that provide process information, revised emission release point coordinate locations and type s (reported as either a stack emission source or a fugitive emission source), and revised stack parameters such as the height or diameter of the stack.

EPA also evaluated the facility-wide risks fo r Steel Pickling facili ties 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. Emission revisions were made for one facility based on the 2005 NATA Risk Preview comments, but not for steel pi ckling processes at the facility. These revisions were not included in the risk analys es, but will be reflected in

the final NATA risk assessment.