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 Shipbuilding and Ship Repair (Surface Coating) 

Maximum Achievable Control Technology (MACT) source category. 

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 Shipbuilding and Ship Repair MACT source category. 

EMISSIONS DATA USED IN RESIDUAL RISK MODELING 

The 2002 National Emissions Inventory (NEI) data served as the starting point for this 

assessment. Using the process MACT code,1 a subset of the NEI was developed that 

contained facility, process, and emissions data 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 released through an Advanced Notice of Proposed 

Rulemaking (ANPRM) in March of 2007, where 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 initial 2005 NATA risk assessment in June of 2009. 

EPA reviewed the results of this analysis, and 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 corresponding to MACT source categories with stationary 

major and area source data. 

1
2

NEI data set for the source category. EPA reviewed the Marine Log publication and 

facility lists from EPA’s Office of Policy, Economics, and Innovation (OPEI) and Office 

of Compliance and Enforcement (OECA) to identify additional major source facilities 

subject to the Shipbuilding and Ship Repair (Surface Coating) NESHAP. The NEI was 

also closely reviewed to identify additional processes with shipbuilding and ship repair 

Source Classification Codes (SCCs), and the NEI 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 data for facilities thought to be subject to the 

rule, but not included in the NEI or TRI databases; 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 that 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 risks associated with 

these facilities. 

EPA then re-modeled the NEI dataset for Shipbuilding and Ship Repair in January of 

2010, and made additional refinements to treat emissions as volume sources for 

modeling, corrected some erroneous location 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 results 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 Shipbuilding and Ship Repair facilities. 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 revisions (removal of emission estimates for a 

process that is not subject to the Shipbuilding and Ship Repair NESHAP) for one 

additional facility that will be made between proposal and promulgation.