Document ID: EPA-HQ-OAR-2017-0684-0012
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2019-06-04T04:00Z

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www.erg.com

MEMORANDUM

TO:	Eric Goehl, Paula Hirtz, Kaye Whitfield, and Kim Teal, U.S. EPA/OAQPS/SPPD

FROM:	Eastern Research Group, Inc.

DATE:	April 22, 2019

SUBJECT:	Documentation for Surface Coating of Metal Can Risk and Technology Review (RTR) Modeling File
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INTRODUCTION
The purpose of this memorandum is to provide information on the Environmental Protection Agency (EPA) Risk and Technology Review (RTR) database used in estimating residual risk for the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Surface Coating of Metal Cans (40 CFR part 63, subpart KKKK). This NESHAP covers only Clean Air Act (CAA) section 112 major sources.
Section 112 of the 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 EPA to develop maximum achievable control technology (MACT)-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 the NESHAP based on the 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 surface coating of metal can source category.
FACILITY LIST DEVELOPMENT
The list of facilities potentially subject to the NESHAP for Surface Coating of Metal Cans was initially developed using the Office of Enforcement and Compliance Assurance's (OECA) Enforcement and Compliance History Online (ECHO) database tool.  The Can Manufacturers Institute (CMI) provided excerpts of operating permits for about 40 facilities that were on the original list for the can coating source category to confirm that only five facilities are major sources subject to 40 CFR part 63, subpart KKKK. The list of the five major source facilities is provided in Appendix A.
RECORDS ASSIGNED TO CATEGORY
After the facility list was complete, emissions data were pulled from 2011 NEI v2. The 2014 NEI v1 data were not available at the time the data were originally compiled; the 2011 NEI v2 were the most recent data available at that time. The Source Classification Codes (SCCs) and unit descriptions were reviewed in order to assign records to the metal can surface coating category. The SCCs and unit descriptions were also used to assign Emission Process Groups in the modeling file. The Emission Process Groups are used to understand the relative contribution of each type of process to the overall risk results after modeling is completed.  After assigning records to the category, one facility did not have HAP emissions associated with the metal can surface coating category. The 2014 NEI v1 was available after the original modeling data were compiled and records assigned to the category, and the 2014 NEI v1 contained HAP emissions for metal can surface coating for this facility.  Therefore, the 2014 NEI v1 data were used for one facility. 
SPECIATION PROFILES
A complete profile of the HAP emissions from metal can coating for the five major source facilities was available in the 2011 NEI v2 and the 2014 NEI v1, therefore, speciation profiles were not needed for this category.
INDUSTRY REVIEW FILE
      The draft modeling file data were provided to CMI for review in December 2016.  In response, we received revisions for two facilities in May 2017. CMI provided revised emissions estimates for one facility, Miller Coors, located in Golden, CO and revised operating hours (hours per year) for two facilities, Miller Coors, Golden, CO, and Ball Metal Beverage Container Corporation, located in Findlay, OH. The Miller Coors revisions included reduced formaldehyde emissions to reflect controls and reduced operating hours for four can coating lines. The Ball revisions included reduced operating hours for one 2-piece steel food can coating line.
QA OF MODELING FILE DATA
In addition to reviewing the modeling file for completeness of pollutants and emissions data, the stack parameters, fugitive dimensions, and locational coordinates were also reviewed and revised as needed.  This review is discussed in detail in sections 6.1 through 6.3.
STACK PARAMETERS
Stack parameter fields include stack (or fugitive) height, exit gas temperature, stack diameter, exit gas velocity, and exit gas flow rate. ERG used the stack parameter data reported in NEI where possible. Where non-fugitive stack parameters were not populated in NEI, the missing values were calculated. For example, a missing flow rate can be calculated using the reported stack diameter and exit gas velocity.
Fugitive vents are required to have the same five stack parameter fields populated in the modeling file. The stack diameter, exit gas velocity, and exit gas flow rate were populated using national default values of 0.003 ft, 0.0003 ft/sec, and 0 actual cubic ft/sec, respectively.  The fugitive vent release type and the fugitive area release type are both required to have a height and exit gas temperature in the modeling file. There were two fugitive vents in the modeling file, and both had a reported temperature of 72 degrees Fahrenheit in NEI.  Where fugitive height was not provided in NEI, we assigned the national default value of 10 ft.
LOCATIONAL COORDINATES
All latitudes and longitudes were mapped and reviewed using Google Earth. A comment from CMI indicated that coordinates for a facility in Weirton, WV were the midpoint between two contiguous facilities. After review of the permit and historical emissions data, ERG confirmed that there is only one major source facility in this location that is subject to 40 CFR part 63, subpart KKKK. The coordinates were corrected based on Google Earth satellite imagery.
EMISSIONS VALUES
No emission data outliers were identified in the initial EPA TREX screening analysis or the final Human Exposure Model (HEM) risk analysis on the category emissions; therefore, no additional QA or investigation was needed. No emission outliers were identified for other process emissions at the facilities not subject to subpart KKKK (i.e., non-category emissions). 
ALLOWABLE EMISSIONS MULTIPLIER
Potential differences between actual emission levels and the maximum emissions allowable under the MACT standard (i.e., "allowable emissions") were calculated for the metal can coating source category. The MACT allowable emissions are the actual emissions multiplied by a factor that represents the difference between the actual emissions, which are based on actual production rates, the HAP content of the coatings and other materials used by the facility, and the coating application method; and the MACT emission limits. 
Metal can coating facilities have a variety of coating operations grouped by subcategory, and each subcategory has emission limits, and several compliance options to meet the emission limits. In the NESHAP, metal can coating operations are divided into four subcategories and those subcategories are further divided into coating type segments, each with its own emission limits. Compliance with the emission limits can be achieved using several different options including: a compliant material option, an emission rate without add-on controls option (averaging option), an emission rate with add-on controls option, or a control efficiency/outlet concentration. 
To use the compliant material option facilities must demonstrate that the organic HAP content of each coating meets the applicable emission limits and that no organic-HAP containing thinners are used. To use the emission rate without add-on controls option, facilities must demonstrate that the total mass of organic HAP in all coatings and thinners in each coating type segment divided by the total volume of coating solids in that coating type segment meets the applicable emission limit. To use the emission rate with add-on controls option, facilities must determine both the efficiency of the capture system and the emissions reduction efficiency of the control device. If facilities use a solvent recovery system, they may determine the overall control efficiency using a liquid-liquid material balance instead of conducting an initial performance test. To use the control efficiency/outlet concentration option, facilities are required to install a control device parameter monitoring system to demonstrate compliance with the efficiency requirement for add-on control systems (95 percent for existing and 97 percent for new sources), or to install and operate a permanent total enclosure (PTE) with 100-percent emission capture efficiency and comply with a control device organic HAP outlet concentration of 20 ppmvd. All metal can coating facilities using add-on controls to comply with the NESHAP emission limitations must also comply with NESHAP work practices to minimize organic HAP emissions from the storage, mixing, and conveying of coatings, thinners, and cleaning materials used in, and waste materials generated by, those coating operations. 
Our review of facility operating permits confirmed that the five major source facilities subject to this NESHAP employ combinations of compliance options. These include the compliant material option for low-HAP coatings (including UV-cured coatings), emission rate without add-on control (averaging option), and add-on controls with the control efficiency/outlet concentration option. Add-on controls include thermal oxidizers (TOs), regenerative thermal oxidizers (RTOs), and a catalytic oxidizer.
Facilities not using control devices are required to use compliant materials that meet the NESHAP emission rate limits, either individually (compliant material option) or collectively (emission rate without add-on controls option), during each monthly compliance period. Based on the review of the facility operating permits, can coating operations for one of the five facilities use compliant materials and do not require add-on controls, so we assumed the actual emissions for this one facility are equal to the NESHAP allowable emissions.
Based on review of the facility operating permits, when a facility-specific compliance option is listed, the NESHAP control efficiency option (95 percent for existing sources and 97 percent for new sources) is the primary option for these control devices. Further review of the facility operating permits shows that emission reductions for a few of the thermal oxidizers are slightly above the control efficiency level required by the NESHAP (in the range of 97 to 99 percent) which suggests that the actual emissions are slightly lower than the NESHAP allowable level for these control devices. For other control devices, control efficiency data were not available. All facility operating permits contained the NESHAP work practice requirements for the storage, mixing, and conveying of coatings, thinners, and cleaning materials used in, and waste materials generated by, those coating operations. Therefore, we assumed the actual emissions are equal to the allowable emissions for those operations. To account for the slightly lower level of actual organic HAP emissions (due to the higher control efficiency of the add-on control devices) we chose to multiply the actual emissions by a factor of 1.1 to represent the allowable emissions from the metal can source category.
ACUTE EMISSIONS MULTIPLIER
As part of the risk assessment analysis, the EPA develops an acute risk estimate that is based on variations in the coating process and the expected highest annual hourly emissions for the source category. We based our estimate on the knowledge we gained about the source category during the RTR review process, site visits, information from can coating facility contacts and the can coating association, and review of facility operating permits.
The can coating industry is mostly a toll industry, where a facility produces cans for many clients. The same basic can coating process is used from facility to facility. The hours of production for each facility are based on customer demand and most run a full 8,760 hours per year. As described above in section 7.0, can coatings are applied in a continuous coating process (not a batch process), resulting in consistent emissions. Therefore, hourly variations in emissions during routine operations are unlikely. We expect there may be slight variations in emissions due to variations in the organic HAP content of the coatings from run to run. To account for this variability, we chose an acute multiplier of 1.1 for the can coating category. Since can coating is a continuous coating process, we don't expect significant changes in hour-to-hour emissions, which is typical of industries with batch operations. The default emission factor of 10 times the annual hourly emission rate is not reasonable for this category. Based on our knowledge of can coating operations we believe that a conservative acute multiplier of 1.1 is appropriate to account for the slight variation in coating composition for this category.
      
      

Appendix A  -  Metal Can Coating Modeling File Facility List
                            EIS FACILITY IDENTIFIER
                                 FACILITY NAME
                               LOCATION ADDRESS
                                     CITY
                                  STATE ABBR
                                  COUNTY NAME
1730011
BWAY Corp
3200 S Kilbourn
Chicago
IL
Cook County
536211
BWAY Packaging
1601 Valdosta Highway
Homerville
GA
Clinch County
6235111
BALL METAL FOOD CONTAINER CORP.
3010 BIRCH DRIVE
WEIRTON
WV
Brooke County
8006111
Ball Metal Beverage Container Corporation 
12340 Township Road 99
Findlay
OH
Hancock County
894811
MILLERCOORS, LLC - GOLDEN BREWERY
12TH ST AT FORD ST
GOLDEN AREA
CO
Jefferson County