MEMORANDUM

TO: Anne Pope, EPA

FROM: Darcy Wilson, ERG

DATE: August 25, 2010

SUBJECT: Emissions Data Used in Residual Risk Modeling for Shipbuilding and Ship Repair (Surface Coating)

The purpose of this memorandum is to provide information on the RTR database used in estimating residual risk for the Shipbuild ing and Ship Repair (Surface Coating)

Maximum Achievable Control Tec hnology (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 Shipbuilding and Ship Repair MACT source category.

EMISSIONS DATA USED IN RESIDUAL RISK MODELING

The 2002 National Emissions Inventory (NEI) data served as the star ting point for this assessment. Using the process MACT code, 1 a subset of the NEI was developed that contained facility, process, and emissions da ta for each facility in the Shipbuilding and Ship Repair (Surface Coating) source category (MACT code 0715-2). The 2002 NEI data for shipbuilding facilities were releas ed through an Advanced Notice of Proposed Rulemaking (ANPRM) in March of 2007, wher e NEI revisions for facilities in the MACT source category were solicited from State and local agencies, industry representatives, and EPA. The revisions that were provided to EPA were then incorporated into the NEI.

Risks associated with facilities covered by the Shipbuilding and Ship Repair MACT

standard were then modeled in the initi al 2005 NATA risk assessment in June of 2009. EPA reviewed the results of this analysis, a nd performed a more in-depth review of the

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.

12 NEI data set for the source category. EPA reviewed the Marine Log publication and facility lists from EPA’s Office of Polic y, Economics, and Innovation (OPEI) and Office of Compliance and Enforcement (OECA) to identify additional major source facilities subject to the Shipbuilding and Ship Repa ir (Surface Coating) NESHAP. The NEI was also closely reviewed to iden tify additional processes with shipbuilding and ship repair Source Classification Codes (SCCs), and the NE I data were compared with data in the EPA’s Toxic Release Inventory (TRI). MACT code and emission revisions were made as a result of these analyses. EPA Regional Offices and State and local agencies were

contacted in an effort to collect emissions da ta for facilities thought to be subject to the rule, but not included in the NEI or TRI da tabases; HAP or volatile organic compound (VOC) estimates were provided for a number of facilities. HAP speciation profiles were applied to the VOC estimates as needed. For facilities in the NEI th at have Shipbuilding and Ship Repair SCCs but EPA could not obtain HAP or VOC emission estimates, EPA applied surrogate HAP emission estimates in order to assess the ri sks associated with

these facilities.

EPA then re-modeled the NEI dataset for Shi pbuilding and Ship Repair in January of 2010, and made additional refinements to treat emissions as volume sources for modeling, corrected some erroneous locati on coordinates, and contacted two State agencies where high-risk facilities were located to confirm emission estimates and emission processes. Additional MACT code and emission revisions were made as a result of these analyses.

EPA also evaluated the facility-wide risks for Shipbuilding and Ship Repair facilities using the 2005 NEI data and risk assessment re sults that were released in the 2005 NATA Risk Preview with State and local agencies in June of 2010. EPA made revisions to remove all emission records for metals, as these HAPs are not associated with surface coating operations at Shipbuild ing and Ship Repair facilitie s. For the most part these revisions were included in the risk analyses, and will be reflected in the final NATA risk

assessment. EPA has also identified revi sions (removal of emission estimates for a process that is not subject to the Ship building and Ship Repair NESHAP) for one additional facility that will be made between proposal and promulgation.