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MEMORANDUM

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

FROM:	Eastern Research Group, Inc.

DATE:	April 26, 2019

SUBJECT:	Documentation for Surface Coating of Metal Coil 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 Coil (40 CFR part 63, subpart SSSS). 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 coil source category.
FACILITY LIST DEVELOPMENT
The list of facilities potentially subject to the NESHAP for Surface Coating of Metal Coil was initially developed using the Office of Enforcement and Compliance Assurance's (OECA) Enforcement and Compliance History Online (ECHO) database tool in January of 2016 and again in 2017.  The ECHO facility list was compared to a list of facilities provided with the original rulemaking. We then reviewed air permits (those available online) to help determine whether each facility remaining on the list is subject to 40 CFR part 63, subpart SSSS. The ECHO searches and permit reviews resulted in a list of 48 facilities subject to subpart SSSS that were included in the modeling file. The list of facilities is provided in Appendix A.
RECORDS ASSIGNED TO CATEGORY
Emissions data were pulled from the 2011 NEI v2 for the original ECHO facility list and from the 2014 NEI v1 for the additional facilities added from the second ECHO search. The 2014 NEI v1 data were not available at the time the data were compiled for the original ECHO facility list; the 2011 NEI v2 were the most recent data available at that time. The Source Classification Codes (SCCs) and unit descriptions were reviewed and compared to air permits, where available, in order to assign records to the metal coil coating category. The SCC 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.
SPECIATION PROFILES
After records were assigned to the category, we performed an overall review of the emissions to determine if the data for each facility were both complete and representative. We found that some facilities reported organic and metal HAP for metal coil coating operations, while others reported only criteria pollutants such as particulate matter (PM) or criteria pollutant precursors such as volatile organic compounds (VOC).
ORGANIC SPECIATION PROFILE
Twenty-two of the 48 facilities in the final modeling file reported both VOC and organic HAP emissions for metal coil coating processes. The emissions for these facilities were used to develop speciation profiles using the weighted-average ratio of each organic HAP to VOC. The HAP-to-VOC ratio was calculated for each organic HAP as the sum of the reported HAP emissions divided by the sum of the reported VOC emissions for those processes with both VOC and HAP. 
The NEI data included some organic HAP that were only reported once in the dataset.  These HAP were excluded from the profile, because they were not considered to be typical or expected for all coil coating facilities. These HAP included N,N-dimethylformamide, tetrachloroethylene, and triethylamine.  These HAP appear in the modeling file only for those facilities that reported them to the NEI.
A small amount of benzene (0.01 lb/yr) was reported for several process IDs related to coil coating at one facility. Because benzene was reported by only one facility, and because this HAP is not expected to be used as a coating solvent or a component of solvent blends, the benzene emissions were excluded from the speciation profile and the modeling file.
Some glycol ether emissions in NEI appear as a generic glycol ether pollutant code, while others reported emissions as 2-butoxyethyl acetate, diethylene glycol monobutyl ether, or butyl carbitol acetate. These pollutants and the generic glycol ether are assigned the same dose response values in risk modeling; thus emissions were combined to calculate a single glycol ether ratio value for the emissions profile.
The speciation profiles were applied to 12 facilities that reported VOC but no organic HAP associated with metal coil coating. The remaining 14 facilities in the category reported organic HAP for metal coil coating but did not report VOC for the same NEI process IDs or the total reported organic HAP exceeded the reported VOC for the process and was considered to be an outlier. The data for these 14 facilities were not used in developing the organic speciation profile.
METALS SPECIATION PROFILE
Two facilities reported emissions of lead and PM10-Primary from metal coil surface coating processes and eight facilities reported emissions of PM10-Primary from metal coil surface coating processes without reporting metal HAP. The facilities with both lead and PM10-Primary were used to develop a speciation profile based on the weighted-average ratio of lead to PM10-Primary. The lead to PM10-Primary ratio was calculated as the sum of the reported lead emissions divided by the sum of the reported PM10-Primary emissions for the processes with both PM10-Primary and lead.  Six facilities reported metal HAPs from metal coil surface coating processes but did not report PM10-Primary for the same processes.  Therefore, the metal HAP emissions from these six facilities were included in the modeling file but were not used in developing the speciation profile.
INDUSTRY REVIEW FILE
The EPA prepared an industry review file and shared it with the National Coil Coating Association (NCCA) for review and comment. In response we received a memo from NCCA that focused on emissions of three HAP: hexavalent chromium, naphthalene and cadmium. The memo is included in the Metal Coil Docket EPA-HQ-OAR-2017-0685.
QA OF MODELING FILE DATA
In addition to reviewing the modeling file for completeness of pollutants and emissions data, the stack and fugitive vent parameters 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.  We used the stack parameter data reported in NEI where possible.  If non-fugitive stack parameters were not populated in NEI, then we first attempted to calculate missing values.  For example, missing flow rate coil be calculated using the reported diameter and velocity.  If there was not enough information to calculate missing values or if reported values were outside of typical QA range check minimum and maximum values, we used averages based on other facilities in the category and approximate stack heights based on satellite imagery or images from Google Street View(C).
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.  If fugitive height or temperature values were not provided in NEI, we assigned national default values of 10 ft and 72 degrees Fahrenheit, respectively.
LOCATIONAL COORDINATES
All latitudes and longitudes were mapped and reviewed using ArcGIS.
EMISSIONS VALUES
The 2011 NEI included emissions of hexavalent chromium for four Precoat Metals (Precoat) facilities. The EPA contacted Precoat and the National Coil Coating Association (NCCA), the industry trade association, to ask specifically about these emissions. No other facilities in the source category reported chromium emissions. The EPA also conducted a site visit to the Precoat facility located in Columbia, South Carolina to review the coil coating operations and potential sources of these emissions. The Precoat representative stated that the hexavalent emissions were not reported by Precoat, but that the Precoat facilities report total chromium and the states and EPA apply different speciation factors to speciate these emissions into trivalent chromium and hexavalent chromium fractions in the inventories. He stated that the chromium releases were primarily offsite disposal releases, not air releases, and that the air releases of chromium were based on the historical assumption that 0.5 percent of the chromium in the applied prime coat was emitted to the air. He stated that this assumption was made by the previous owners of the facilities and that Precoat had continued to use this factor. The factor was not based on any measured emissions, no testing was ever conducted, and no analytical data exist to support the factor. The NCCA confirmed that the hexavalent chromium emissions were the result of state-applied and EPA-applied factors to the total chromium reported by the facilities but that the coil coating processes and the oven temperatures did not support the emissions of hexavalent chromium reflected in the dataset. 
During the Precoat site visit, EPA observed the coil coating application and curing processes. EPA observed that once the metal coil is cleaned, it goes through a pretreatment process consisting of a wet process followed by a dry process. The wet process consists of a series of inorganic chemical baths (can be either Ni/Zn or Ni/Zn/phosphate), followed by a dry chromic acid process that is roll applied to prepare the surface for coating. The following coating application process includes primers, some of which contain strontium chromium, that are also roll applied. The oven curing temperature for the prime coat at Precoat facilities vary depending on line speed but were reported to range well below temperatures that would cause any emissions of hexavalent chromium. 
Because no data were available to support the use of this factor, and because there is no identifiable mechanism to cause these emissions (e.g., the material is roll applied and is not spray applied and oven temperatures are sufficiently low), the EPA did not apply chromium emissions to other facilities in the source category and removed these emissions from the modeling file.
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 coil 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, the coating application method, and the add-on control device destruction efficiency or outlet concentration) and the MACT emission limits. 
    The portions of the metal coil coating line to which the NESHAP emission limits apply are the coating application stations and associated curing ovens. Compliance with the NESHAP emission limits can be achieved using several different options including: a compliant material as-purchased or as-applied (averaging) option, an emission rate with add-on controls option or a combination option of compliant coatings and an add-on control device. The standard also establishes operating limits for capture systems and add-on control devices. The compliance options apply to an individual coil coating line, to multiple lines as a group, or to the entire affected source.
    To use the as-purchased compliant material option facilities must demonstrate that the organic HAP content of each individual coating meets the emission limit (0.046 kg of organic HAP per liter solids). To use the as-applied compliant material option, facilities must demonstrate that the average of each coating or the average of all coating materials applied meets the emission limit (0.046 kg of organic HAP per liter solids). To use the emission rate with add-on controls option, facilities must demonstrate 1) an overall control efficiency of 98 percent or 2) an outlet concentration of 20 ppmv as carbon and 100 percent capture efficiency. (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 any compliance option involving an add-on control, except for a solvent recovery system and using a material balance, facilities are required to install control device parameter monitoring system equipment to demonstrate compliance with operating limits established for the emission capture and control systems. 
    During development of the 2002 MACT, the EPA conducted a survey and results were received from 89 major source coil coating facilities operating a total of 105 coil coating lines.  According to the survey results, 75 percent of the coil coating lines employed the use of thermal oxidizers to control organic emissions, 23 percent of the coil coating lines used catalytic oxidizers and 2 percent used condenser/scrubber systems. 
    As part of the RTR rulemaking process, operating permits for 39 major source coil coating facilities were reviewed and 37 were found to employ the use of add-on controls. Three of the operating permits showed that not all coating lines had add-on controls which indicates the facilities are complying with the NESHAP emission limits using the compliant material option or the emission averaging option.  
    The primary add-on controls for these 37 facilities are thermal oxidizers, regenerative thermal oxidizers, and catalytic oxidizers. Based on review of the facility operating permits, when a facility specific compliance option is listed, the control efficiency option (98 percent) is the primary option for these control devices. Further review of the facility operating permits show that emission reductions for several thermal oxidizers are performing slightly above the 98 percent control efficiency level required by the NESHAP (in the range of 98.5 to 99.9 percent) which suggests that the actual emissions are slightly lower than the NESHAP allowable level for these control devices. For the majority of the facilities the control efficiency from the initial performance test, or most recent performance test, if periodic testing is required, was not available. All facility operating permits reflected the NESHAP requirements for add-on control devices. For each add-on control, we concluded that the organic HAP emissions were either equal to or slightly lower than the MACT allowable levels.

    Three of the operating permits showed that not all coating lines had add-on controls which indicates that the facility was complying with the NESHAP emission limits using the compliant material option or the emission averaging option. Facilities using these options are required to use compliant materials that meet the NESHAP emission rate limit (0.046 kg of organic HAP per liter solids), either individually or collectively, during each monthly compliance period. For these processes we believe the actual emission levels for these metal coil coating operations are a reasonable estimation of levels allowed by the NESHAP.
    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 factor of 1.1 to represent the allowable emissions from the metal coil 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 coil coating facility contacts and the coil coating association, and review of facility operating permits.
The coil coating industry is mostly a toll industry, where a facility produces painted coil for many clients. The coil coating category is process specific, meaning the same basic process is used from facility to facility. The hours of production for each facility are based on customer demand, so some facilities run 12-hour shifts, while others run a full 8,760 hours per year. As described above in section 7.0, most coil coating operations roll-apply prime coat and finish coat to a moving metal strip (coil) in a continuous coating process (long batches) inside enclosures that are routed to add-on control devices. The coated coil is then cured in an oven that is routed to an add-on control device. Coil coating operations for three facilities roll apply compliant materials (as-purchased or as-applied) and do not require add-on controls. 
The coils are seamed together end to end for continuous runs, resulting in consistent emissions. 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 coil coating category. Since coil 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. We believe that a default acute multiplier of 10 is not reasonable and does not appropriately represent the variation in hourly emissions for the coil coating category. Based on our knowledge of coil 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 Coil Coating Modeling File Facility List
                            EIS Facility Identifier
                                 Facility Name
                               Location Address
                                     City
                                     State
                                    County
10642311
Precoat Metals
5888 East County Road 180
Blytheville
AR
Mississippi County
12577111
Precoat Metals Division Sequa Corporation
3399 Davey Allison Blvd
Hueytown
AL
Jefferson County
13431011
MSC Walbridge Coatings Inc (0387000046)
30610 East Broadway
Walbridge
OH
Wood County
16808311
Metal Coaters (1409000037)
2400 Yankee Road
Middletown
OH
Butler County
1866611
Wismarq Corp
11440 Addison St
Franklin Park
IL
Cook County
2551411
Signode Corp
7701 W 71st St
Bridgeview
IL
Cook County
2994211
Nichols Aluminum - Davenport - Rockingham Rd
1725 Rockingham Rd
Davenport
IA
Scott County
4019511
Precoat Metals Houston
16402 Jacinto Port
Houston
TX
Harris County
4785611
NCI Group Inc., Dba, Metal Coaters of CA
9133 Center Ave
Rancho Cucamonga
CA
San Bernardino County
4800211
Fuji Film Inc P Plant
211 Puckett Ferry Rd
Greenwood
SC
Greenwood County
5276311
Wolverine Gasket Division - Eagle-Picher Ind
3175 State Street
Blacksburg
VA
Montgomery County
5344111
Aleris Rolled Products Inc
1372 KY 1957
Lewisport
KY
Hancock County
5344211
Precoat Metals
2604 River Rd
Hawesville
KY
Hancock County
5694311
Wolverine Advanced Materials  -  Blacksburg
201 Industrial Park Rd
Blacksburg
VA
Montgomery County
6068311
Wismarq Corporation
930 Armour Rd
Oconomowoc
WI
Waukesha County
6234611
Wheeling Corrugating Company
West Virginia Route 2
Beech Bottom
WV
Brooke County
6235311
Precoat Metals
4502 Freedom Way
Weirton
WV
Brooke County
6263011
Edco Products Inc
8700 Excelsior Blvd
Hopkins
MN
Hennepin County
641911
Wolverine Advanced Materials
10825 County Road 44
Leesburg
FL
Lake County
6559911
Alumax Mill Prod Inc/Mill Prod
1480 Manheim Pike
Lancaster
PA
Lancaster County
6654511
Consolidated Systems, Inc
650 Rosewood Dr
Columbia
SC
Richland County
7212211
Constellium
3509 E 2nd St
Muscle Shoals
AL
Colbert County
7249611
Precoat Metals A Division Of Sequa Corp
1950 E Main St
Greenfield
IN
Hancock County
7304011
Precoat Metals-Precoat Metals
4301 S Spring
St. Louis
MO
St. Louis City
7316911
Material Sciences Corp
2300 E Pratt Blvd
Elk Grove Village
IL
Cook County
7330811
Novelis Corporation (0278080136)
390 Griswold Street, N.E.
Warren
OH
Trumbull County
7376711
Precoat Metals Division Sequa Coatings
6300 Us Hwy 12
Portage
IN
Porter County
7409411
US Steel Corp/Irvin Plt
Camp Hollow Rd
Dravosburg
PA
Allegheny County
7745111
Edcoat Limited Partnership
30350 Edison Road
New Carlisle
IN
St. Joseph County
7746911
USG Interiors, Inc., Americoil Metals Corp., Westlake (1318617346)
1000 Crocker Rd.
Westlake
OH
Cuyahoga County
7822411
Vulcraft Of New York Inc
5362 Railroad St
Chemung
NY
Chemung County
7874411
Brightsmith Llc/Falls Twp
120 Enterprise Ave
Morrisville
PA
Bucks County
7882611
Precoat Metals
25 Northgate Industrial Dr
Granite City
IL
Madison County
7891111
Alcoa Inc
4879 State St
Riverdale
IA
Scott County
7905611
Agfa Corporation
50 Meister Ave
Branchburg
NJ
Somerset County
7972711
Precoat Metals Corp.
2nd Rd & Hupp Rd
La Porte
IN
La Porte County
8109311
Logan Aluminum Inc
6920 Lewisburg Rd
Russellville
KY
Logan County
8115811
Ak Steel - Zanesville Works (0660010006)
1724 Linden Avenue
Zanesville
OH
Muskingum County
8163211
Aleris Rolled Products, Inc. (0165000045)
1 Reynolds Road
Ashville
OH
Pickaway County
8181811
Alcoa Inc. - Warrick Operations
State Road 66 & State Road 61
Newburgh
IN
Warrick County
8230511
Precoat Metals
1095 Mendell Davis Drive
Jackson
MS
Hinds County
8235311
Jupiter Aluminum Corporation Jupiter 
205 E Carey St
Fairland
IN
Shelby County
8267211
Crown Cork & Seal (0448010466)
5201 Enterprise Blvd
Toledo
OH
Lucas County
8373611
Centria (0630010006)
530 North Second Street
Cambridge
OH
Guernsey County
8405611
Springs Window Fashions/Montgomery Plt
8601 State Route 405
Montgomery
PA
Lycoming County
8463911
Ply Gem (0575010103)
2615 Campbell Road
Sidney
OH
Shelby County
8499411
Metal Coaters
951 Prisock Road
Byram
MS
Hinds County
948011
Southwire Company  - Carrollton
One Southwire Drive
Carrollton
GA
Carroll County

