                                                                               
MEMORANDUM


DATE:	April 24, 2019

SUBJECT:	Technology Review for Surface Coating Operations in the Metal Can Category

FROM:	Eastern Research Group, Inc.

TO:		Paula Hirtz, OAQPS/SPPD/MMG


1.0	INTRODUCTION	

Section 112 of the Clean Air Act (CAA) requires the U.S. Environmental Protection Agency (EPA) to establish technology-based national emission standards to control hazardous air pollutants (NESHAP) for listed source categories. These technology-based standards are often referred to as maximum achievable control technology (MACT) standards. The Metal Can NESHAP (40 CFR part 63, subpart KKKK) regulates HAP emissions from facilities that are major sources and are engaged in the surface coating of metal cans. The rule requires the use of MACT to reduce HAP emissions from the following operations: mixing; coating; curing; conveying coatings, thinners and cleaning materials; and waste storage and handling. The Surface Coating of Metal Can NESHAP, hereafter referred to as the Metal Can NESHAP, regulates HAP emissions from facilities that are major sources of HAP and are engaged in the surface coating of metal cans. The final NESHAP was promulgated on November 13, 2003 (68 FR 64432). Technical corrections and clarifying amendments were proposed and promulgated on January 6, 2006 (71 FR 1378).

Pursuant to 40 CFR 63.3481, the NESHAP requires the use of MACT to reduce HAP emissions from the surface coating of metal cans and ends (including decorative tins) and metal crowns and closures. It includes 4 subcategories: 1) one- and two-piece draw and iron can body coating, 2) sheet coating, 3) three-piece can body assembly coating, and 4) end coating. Facilities conducting can coating operations are subject to the NESHAP if they are a major source and use 1,500 gallons per year or more of coatings.

Section 112 also contains provisions requiring the EPA to periodically revisit these standards. Specifically, section 112(d)(6) states:

      REVIEW AND REVISION.  -  The Administrator shall review and revise as necessary (taking into account developments in practices, processes, and control technologies), emissions standards promulgated under this section no less often than every 8 years.

To comply with this CAA requirement, the EPA conducted a technology review for the Metal Can NESHAP for major sources. This memorandum addresses the technology review for all metal can surface coating operations and subcategories.

For the purposes of this technology review, the EPA considers a "development" in practices, processes, and control technologies to be:

 Any add-on control technology or other equipment that was not identified and considered during MACT standard development;
 Any improvements in add-on control technology or other equipment (that was identified and considered during MACT standard development) that could result in additional emission reduction;
 Any work practice or operational procedure that was not identified and considered during development of the original MACT standard; 
 Any process change or pollution prevention alternative that could be broadly applied to the industry that was not identified and considered during MACT standard development; and
 Any significant changes in the cost (including cost effectiveness) of applying controls (including controls the EPA considered during the development of the original MACT standards).

Section 2 of this memorandum presents a summary of the sources of data that were used to conduct the technology review and Section 3 presents the can coating process description, the existing level of MACT control and control measures identified for the technology review for metal can surface coating operations. 

2.0	SOURCES OF AVAILABLE CONTROL TECHNOLOGY INFORMATION

To identify any developments in practices, processes, or control technologies that could be applicable to surface coating operations in the metal can industry, we consulted the following sources of data: RACT/BACT/LAER Clearinghouse, regulatory actions promulgated for other surface coating NESHAP subsequent to the metal can surface coating NESHAP, regional and state regulations, operating permits, site visits, and information from individual facilities and the industry trade association. .  

2.1	RACT/BACT/LAER Clearinghouse Database

Under the EPA's New Source Review (NSR) program, if a company is planning to build a new plant or modify an existing plant such that their criteria air pollution emissions will increase by a certain amount, then the company must obtain an NSR permit. The NSR permit is a construction permit which generally requires the company to minimize these emissions by changing the process to prevent air pollution and/or installing air pollution control equipment. 

The terms "RACT," "BACT," and "LAER" are acronyms for different program requirements relevant to the NSR program.  RACT, or Reasonably Available Control Technology, is required on existing sources in areas that are not meeting national ambient air quality standards (NAAQS) (non-attainment areas). BACT, or Best Available Control Technology, is required on new or modified major sources in areas meeting NAAQS (attainment areas). LAER, or Lowest Achievable Emission Rate, is required on new or modified major sources in non-attainment areas. 

BACT and LAER (and sometimes RACT) are determined on a case-by-case basis, usually by state or local permitting agencies. The EPA established the RACT/BACT/LAER Clearinghouse, or RBLC, to provide a central database of air pollution technology information (including past BACT and LAER decisions contained in NSR permits) to promote the sharing of information among permitting agencies and to aid in future case-by-case determinations. However, the RBLC is not limited to sources subject to RACT, BACT, and LAER requirements. It can include noteworthy pollution prevention and control technology decisions and information on cost effectiveness. 

The RBLC contains over 5,000 air pollution control permit determinations that can help identify appropriate technologies to mitigate most air pollutant emission streams. It was designed to help permit applicants and reviewers make pollution prevention and control technology decisions for stationary air pollution sources, and includes data submitted by several U.S. territories and all 50 states on over 200 different air pollutants and 1,000 industrial processes.
	
The RBLC provides several options for searching the permit database on-line to locate control technologies that are applicable to a specific source category. On August 16, 2016, we conducted a search of the RBLC to locate any potential advances in control technologies employed by sources in the metal can surface coating category, with permits dating back to 1990.  The search results included the following data fields:
 
::	RBLC ID
::	Facility Name, and State
::	Permit Date
::	Process name
::	Throughput
::	Pollutant
::	Control technology
::	Percent efficiency of control

The search (which used a start date of January 1, 2000) provided only four metal can facilities, which all had permit dates of 2006 or later. All four of the results contained information about the add-on controls. Of these facilities, two reported the use of regenerative thermal oxidizers (RTOs), one reported the use of an induction heater and catalytic oxidation and one reported the use of thermal oxidation. The results of the search are consistent with current Metal Can NESHAP requirements and are presented in Table 1 for the metal can source category.

Table 1. Practices, Processes and Control Technologies Identified for Metal Can Coating Operations in the October 21, 2016, Query of the RBLC Database
                                    RBLCID
                                 (Permit Date)
                                       
                                 Facility Name
                                       
                                     State
                                       
                                 Process Name
                                       
                                   Pollutant
                                Control Method
                       VOC Emission Reduction (%) [(a)]
                                    FL-0353
                                  (11/10/15)
                          Metal Container Corporation
                                      FL
                         Aluminum Bottle Coating Line
                                      VOC
                            Capture system with RTO
                                      69%
(73% capture and 95% DRE)
                                    TX-0586
                                  (09/02/10)
                   Ball Metal Beverage Container Corporation
                                      TX
                           Can Manufacturing Line #3
                                      VOC
                               Thermal oxidation
                                     78.4%
(80% capture and 98% DRE)
                                    CO-0065
                                  (10/11/06)
                        Rocky Mountain Metal Container
                                      CO
                                 C24 Can Line
                                      VOC
                                      RTO
                                      76%
(not specified, but assumed to be 80% capture and 95% DRE)
                                       
                                    TN-0158
                                  (06/28/06)
                                Sonoco-Phoenix
                                      TN
                             Can End Manufacturing
                                      VOC
                   Induction heater and catalytic oxidation
                                      72%
(not specified, but assumed to be 80% capture and 90% DRE)
[(a)] These reductions are permit limits which specify a minimum overall control efficiency based on separate  
     capture efficiency and destruction/removal efficiency (DRE), and do not reflect actual performance.

Developments identified in the regulatory actions listed in Table 1 above are discussed in Section 3 (Technology Review for Surface Coating Operations).

2.2	Subsequent Regulatory Actions

Regulatory actions promulgated subsequent to the 2003 Metal Can NESHAP were identified for sources similar to metal can coating sources. These regulatory actions, listed in Table 2, were reviewed for any developments in practices, processes and control technologies that might apply to metal can coating.

Table 2. Subsequent Regulatory Actions for Sources Similar to Metal Can Coating Operations
                                 MACT Standard
                                    Subpart
                                 Promulgation
                                     Date
           Practices, Processes, and Control Technologies Evaluated
           Surface Coating of Miscellaneous Metal Parts and Products
                                     MMMM
                                   1/2/2004
Emission limit as mass HAP per volume solids used. Controls include low-HAP coatings, ultraviolet (UV) curable electron beam (EB) curable coatings, powder coatings, add-on controls.
                 Surface Coating of Plastic Parts and Products
                                     PPPP
                                   4/19/2004
Emission limit as mass HAP per mass solids used. Controls include low-HAP coatings, UV and EB curable coatings, add-on controls.
             Surface Coating of Automobiles and Light-Duty Trucks
                                     IIII
                                   4/26/2004
Emission limit as mass HAP per volume solids deposited. Develop and implement a work practice plan to minimize organic HAP. Controls include low-HAP coatings, high efficiency application methods, and add-on controls.
                      Technology Review of MACT Standard
                                    Subpart
                                 Promulgation
                                     Date
  Practices, Processes, and Control Technologies Identified as Developments 
                                 Magnetic Tape
                                      EE
                                   4/07/2006
                                No developments
                            Printing and Publishing
                                      KK
                                   4/21/2011
          Permanent total enclosures installed on controlled presses
                         Shipbuilding and Ship Repair
                                      II
                                  11/21/2011
 Concentrator/RTO installed on spray booths to achieve 95% control efficiency.
                         Wood Furniture Manufacturing
                                      JJ
                                  11/21/2011
RTO; Lower VOC coating limits based on California regional rules, more efficient spray guns.
                 Aerospace Manufacturing and Rework Facilities
                                      GG
                                   12/7/2015
                                No developments

2.3 Review of Major Source Can Coating Facility Operating Permits

Using a collection of data sources, including the EPA's Enforcement and Compliance History Online (ECHO), the 2011 National Emission Inventory (NEI) NEI version 2 database, and facility operating permits. A total of 5 facilities in 5 states were identified as major sources with metal coil coating operations. Review of the state operating permits that were available on-line revealed that 3 of the 5 facilities use add-on controls and 2 of the 5 facilities use the compliant material option or the emission rate without add-on controls (averaging) option to meet the NESHAP emission limits. Table 3 summarizes the compliance options and controls used by the 5 major source facilities. 

Table 3. Summary of the compliance options and controls used by major source facilities subject to subpart KKKK
                                   Facility
                               Permit Conditions
                                       
                        Subpart KKKK Compliance Option
                     Control Device Destruction Efficiency

Rocky Mountain Metal Container (Miller-Coors), Golden CO
Not specified in permit; however, the technical support document for the 2006 permit indicates that non-UV cured coating operations are vented to an RTO; UV-cured coating operations are not vented to the RTO.
Compliant Material or Emission Rate without Add-on Control, and Add-on Control
                                 Not specified
BWAY Packaging, Homerville, GA
Not specified in permit; however, the facility has RTOs on the lithographic printing and coating lines which are subject to both KKKK and MMMM; no controls on the can line subject to only KKKK.
Compliant Material or Emission Rate without Add-on Control
                                      N/A
BWAY Corp, Chicago, IL
Lithography lines use the control efficiency/outlet concentration option as long as consent decree is in effect.

Add-on Control Option
Thermal Oxidizer (Line 1) Catalytic Oxidizer (Lines 2, 3, and 4): 95% or 20 ppmv THC per 63.3491(d)

Ball Metal Beverage Container Corporation, Findlay, OH

Can lines 1 and 2 (2-Piece aluminum beverage cans) and can line 3 (2-piece steel food cans) use the compliant material option or emission rate without add-on controls option.
Compliant Material or Emission Rate without Add-on Control
                                      N/A
Ball Metal Food Container Corp, Weirton, WV
Compliance options used as of permit renewal issuance date (9/11/2012): 

Sheet Coaters and Ovens, C-1, C-2, C-3, C-4: control efficiency/outlet concentration option.
End Liners MD-1, MD-5, MD-3, MD-4, and MD-2: compliant materials option.
LTG-1 [Sheetcoating] Coater and Oven: control efficiency/outlet concentration option.
Sheet coaters C-5, C-6, C-7, C-8, C-9, and C-10: control efficiency/outlet concentration option.
Planeta Press [Sheetcoating]: emission rate without add-on controls option.
Press-Coater-Oven [Sheetcoating] Lines PC-3, PC-4, PC-5, PC-6, and PC-7: Emission rate with add-on control options.





Compliant Material, Emission Rate without Add-on Control, and Add-on Control 
Control efficiency/outlet concentration option: thermal oxidizer: 95% or 20 ppmv THC per 63.3491(d)

2.4 Site Visits

The EPA conducted one site visit to the Ball Metal Beverage Container Corporation located in Findlay, Ohio, to support this technology review.  The site visit report is available for review in the Metal Cans docket (Docket ID No. EPA-HQ-OAR-2017-0684).

2.5 Industry Information

We gathered industry background information from a variety of sources to support the can coating technology review including the Can Manufacturers Institute (CMI) and the American Coatings Association's Industry Market Analysis, 9th edition (2014-2019). The CMI is the industry's trade association. 

Industry Background

The ACA market analysis of the can coating industry is concentrated in Chapter 17 titled "Metal Container and Closure Finishes," and includes food and beverage cans, metal drums and pails, metal collapsible tubes, and closures for bottles, jars and cans. The market analysis looks at several different metal container segments. The beer and beverage container segment accounts for approximately 51 percent of the metal container coating market by volume, according to the market analysis. The food and general packaging segment accounts for approximately 33 percent (27 percent food and 6 percent general). General packaging includes aerosol and other non-food cans. Coatings for closures accounts for 4 percent of the volume. (It also includes coatings for pail and drum coatings, which account for 11 percent of metal container coating volume, and metal tube containers, which account for 1 percent, but these are not part of the can coating source category). 

The analysis notes that the demand for metal cans has declined while the population and economy have grown because of a shift to rigid and flexible plastic packaging, such as plastic soda bottles and plastic food pouches and containers. The market analysis reports that the amount of coating used per can has stabilized, after a slight downward trend since 2010, based on testing which showed that going to lower film weights per can would not provide sufficient performance. Can coating operations are not subject to trade influences, except in the case of crowns, closures and seals, according to the market analysis. These items can be produced outside the U.S. and imported. For beer and beverage containers, alternatives to metal cans exist in the form of glass and plastic bottles. The market analysis notes that reduced consumption of soft drinks in metal cans was offset by an increased use of metal cans over bottles for craft beers. The market analysis also notes the emergence of metal "bottle cans" but these are a small segment of the market and are more expensive to produce than standard metal cans.

Coating Chemistry Background

A variety of coating chemistries are used in the can coating market. The 1977 control techniques guidelines document (CTG) for "Control of Volatile Organic Emissions from Existing Stationary Sources  -  Volume II: Surface Coating of Cans, Coils, Paper, Fabrics, Automobiles, and Light-Duty Trucks" (EPA-450/2-77-008) and the 1983 new source performance standard (NSPS) for two-piece beverage can surface coating (40 CFR 60, subpart WW) provided the incentive to develop alternatives to conventional solvent borne can coating formulations. These alternatives included higher solids coatings, waterborne coatings and ultraviolet (UV) and electron beam (EB) cured coatings for some can coating applications. Interior coatings used for cans that contain food or beverages are subject to regulation by the US Food and Drug Administration (US FDA), as well as internal approval by the food and beverage manufacturers. Each coating alternative is discussed in more detail below.

Powder Coatings
The market analysis covers the use of coil coatings for metal containers and closures but does not include the use of powder coatings because powder coating applications are not common for metal container coatings. The market analysis states that a small, and declining, amount of powder is used, principally for side seams in 3-piece cans. 

Ultraviolet (UV) and Electron Beam (EB) Curable Coatings
The market analysis reports that other available technologies include UV- or EB-curable coating systems and estimate that about 4 percent of can coatings were based on these technologies and does not expect growth. UV-curable coatings are used on aerosol can exteriors and on exterior rim coatings. Some EB-curable coatings can now be used on certain can interiors because they do not contain the photo-initiator compounds that were potentially harmful if released into the content of the cans. Until recently UV-curable coatings were not approved by the FDA for use in interior coatings due to this reason. The market analysis reports that future growth is still limited by significant capital cost (especially UV equipment), and there are only certain parts of a container that can be coated with energy-cured systems, because of a variety of regulations, taste considerations and functional performance issues.

High Solids Coatings
The market analysis does not discuss the use of high solids coatings, but the information we gathered during the 2002 MACT development showed that high-solids coatings were used for sheet applied interior coating for 3-piece cans containing certain food and non-food products, interior side seam stripes for 3-piece cans, end seal compounds, and exterior side seam stripe coatings. Some conventional solvent borne coatings were still in use for 3-piece can exterior sheet coating, where high abrasion resistance is required or when the metal is subsequently subjected to fabrication. Conventional solvent-borne inks and interior coatings were also in use at that time, and contained VOC, but no HAP. 

Waterborne Coatings
The market analysis reports that in the food can and general packaging segments, three-piece cans will continue to be replaced by two-piece cans which results in the decreased use of side-seam coatings and increased use of waterborne coatings on can bodies. The growth in 2 piece can construction is expected to result in increased consumption of waterborne coatings. Closures will continue to use pre-coated coil stock and the predominant coatings will continue to be solvent-based epoxy and epoxy-phenolic coatings. Waterborne coating application processes are generally not fast enough for can coating line speeds.

Coatings containing Bis-phenol A 
The market analysis states that the primary technology change in the metal can surface coating category is the development and potential future application of coatings that have no intentionally added bis-phenol A (BPA) for both beverage and food cans, referred to as BPA-NI coatings. These coatings are under development to replace current BPA-containing coatings but had not been adopted at the time the market analysis was prepared. The market analysis reports that the major can coatings producers are currently devoting much of their research and development efforts to develop BPA-NI systems for new applications and to improve the BPA-NI systems that already exist. However, the market analysis reports that a complete shift to these coatings is not expected unless driven by US FDA regulation or consumer opinion. 

The market analysis reports that there are numerous acceptable BPA-NI formulations available, but they are not widely used. They are currently used for niche applications, such as for foods specifically labeled as "organic." Coating formulators are spending the majority of their time working on improving these products, even though most are not yet in commerce. Both the US FDA and the European Food Safety Authority have determined that currently used coatings are acceptable with respect to BPA at current levels. Only France has mandated the use of BPA-NI coatings.

The market analysis predicts that any pressure to use BPA-NI coatings may lead to a shift to polyester and acrylic coatings and away from epoxy acrylics, epoxy phenolics, and epoxies, which all contain BPA, but this shift will be slow and will not be for all industry segments, especially the segments that use the most coatings. However, interior coatings for cans that contain food or beverages are subject to regulation by the FDA, as well as internal approval by the food or beverage manufacturers. This process can take as long as 5 years for interior coatings, according to the market analysis, and would slow the shift to new types of coatings. The market analysis also notes that because can manufacturing plants run at very high speeds, the can coatings must meet stringent performance requirements during application, as well as after the cans are manufactured and put into use. 

The market analysis did not reveal whether the BPA-NI coatings formulations would be considered compliant materials but it predicts that coating consumption could increase if there is a shift to BPA-NI coatings because of the use of increased film thickness to achieve the same performance as currently used coatings. The thicker films, with an equivalent performance to coatings currently in use would not necessitate new coating application technologies. The CMI stated that new BPA-NI formulations should not require a new application technology. 

3.0	TECHNOLOGY REVIEW FOR SURFACE COATING OPERATIONS

The HAP emissions from the metal can category occur from coating application lines, drying and curing ovens, mixing and thinning areas, and cleaning of equipment. The exterior base coat for two and three-piece cans is applied in a lithographic/printing (i.e., roll) application process. Inside and repair spray coating using high efficiency airless spray equipment are a minor portion of the can coating operations. As indicated by the name, repair spray coatings are used to cover breaks in the coating that are caused during the formation of the score in easy-open ends or to provide, after the manufacturing process, an additional protective layer for corrosion resistance.

As defined in the Metal Can NESHAP, a coating is a material that is applied to a substrate for decorative, protective or functional purposes. Such materials include, but are not limited to, paints, sealants, caulks, inks, adhesives, and maskants. The primary HAP emitted from metal can surface coating operations included glycol ethers, xylenes, hexane and methyl isobutyl ketone (MIBK). Chemical reactions that commonly occur during metal can coating and curing operations may create compounds commonly referred to as "cure volatiles" or "cure HAP" and may include formaldehyde and methanol. 

Ethylene glycol monobutyl ether (EGBE) and methyl ethyl ketone (MEK) were also used as solvents in these coatings, but both compounds were removed from the HAP list. EGBE was delisted in November 2004 and MEK was delisted in December of 2005. The delisting of these HAP had a major impact on the list of major sources, pursuant to 40 CFR 63.3483(b), because the compliance date for existing metal can surface coating sources was November 13, 2006, after the EGBE and MEK delisting dates. 

3.1	Summary of Existing MACT Level of Control

The Metal Can NESHAP standard applies to: 1) all coating operations; 2) all storage containers and mixing vessels in which coatings, thinners, and cleaning materials are stored or mixed; 3) all manual and automated equipment and containers used for conveying coatings, thinners, and cleaning materials; and 4) all storage containers and all manual and automated equipment and containers used for conveying waste materials generated by a coating operation.

Table 4 lists the organic HAP content limits required by the 2003 Metal Can NESHAP (subpart KKKK) for each can coating subcategory. Alternatively, a capture and control system can be used to control emissions. The capture and control system must achieve an overall control efficiency of 97 percent for a new or reconstructed source and 95 percent for an existing source or limit the emissions of total HAP to 20 ppm by volume dry (ppmvd) at the control device outlet and use a permanent total enclosure.  

Table 4. Summary of Emission Limits in Subpart KKKK
       If you apply surface coatings to metal cans or metal can parts in
                             this subcategory ...
                            Then for all coatings 
                               of this type ...
New and reconstructed sources must meet the following organic HAP emission limit in kg HAP/liter solids (lbs HAP/gal solids):[a] b
Existing sources must meet the following organic HAP emission limit in kg HAP/liter solids (lbs HAP/gal solids):[a] b
1. One and two-piece draw and iron can body coating
a. Two-piece beverage cans -- all coatings
                                  0.04 (0.31)
                                  0.07 (0.59)

b. Two-piece food cans -- all coatings
                                  0.06 (0.50)
                                  0.06 (0.51)

c. One-piece aerosol cans -- all coatings
                                  0.08 (0.65)
                                  0.12 (0.99)
2. Sheet coating
Sheet coating
                                  0.02 (0.17)
                                  0.03 (0.26)
3. Three-piece can assembly
a. Inside spray
                                  0.12 (1.03)
                                  0.29 (2.43)

b. Aseptic side seam stripes on food cans
                                 1.48 (12.37)
                                 1.94 (16.16)

c. Non-aseptic side seam stripes on food cans
                                  0.72 (5.96)
                                  0.79 (6.57)

d. Side seam stripes on general line nonfood cans
                                  1.18 (9.84)
                                  1.18 (9.84)

e. Side seam stripes on aerosol cans
                                 1.46 (12.14)
                                 1.46 (12.14)
4. End coating
a. Aseptic end seal compounds
                                  0.06 (0.54)
                                  0.06 (0.54)

b. Non-aseptic end seal compounds
                                  0.00 (0.00)
                                  0.00 (0.00)

c. Repair spray coatings
                                  0.64 (5.34)
                                 2.06 (17.17)

There are four options for complying with the emission limits, and the testing and initial compliance requirements vary accordingly. 

 Option 1 - Compliant Material Option. 
 Demonstrate that the organic HAP content of each coating meets the applicable emission limits and that you use no organic-HAP containing thinners.
 Option 2 - Emission Rate without Add-on Controls. 
 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.
 Option 3 - Emission Rate with Add-on Controls. 
 Determine both the efficiency of the capture system and the emissions reduction efficiency of the control device. If you use a solvent recovery system, you may determine the overall control efficiency using a liquid-liquid material balance instead of conducting an initial performance test.
 Option 4 - Control Efficiency/Outlet Concentration. 
 Option 3 plus, for add-on control systems, you are required to install control device parameter monitoring system (CPMS) equipment to be used to demonstrate compliance. Using the data collected with the CPMS, you must calculate and record the average values of each operating parameter according to the specified averaging times.

In addition, if an affected source uses the emission rate with add-on controls option, subpart KKKK requires the development and implementation of a work practice plan that minimizes organic HAP emissions from the storage, mixing and conveying of coating, thinners and cleaning materials used in, and the waste materials generated by, the coating operation. 

3.2	Identified Control Measures for Surface Coating Operations

The practices, processes, and control technologies evaluated for rules promulgated subsequent to metal can (the area source rules and NESHAP listed in Table 2 above) are discussed in the following sections. We evaluated these emission reduction techniques to determine if they could potentially apply to metal can coating. 

3.2.1	Add-On Control Technology or Other Equipment Not Identified and Considered During MACT Development

Inorganic HAP Emissions

Inorganic HAP emissions were considered in the development of the Metal Can NESHAP and the EPA determined that no controls were needed because the coatings used that may contain inorganic HAP were not spray applied. Instead, these coatings were roll applied through direct contact (similar to lithographic printing) with the surface to which they were being applied and the inorganic HAP became part of the cured coating.

Two subsequent area source rules, Paint Stripping and Miscellaneous Surface Coating Operations Area Source Rule (40 CFR 63 subpart HHHHHH) and Nine Metal Fabrication and Finishing Source Categories Area Source Rule (40 CFR 63 subpart XXXXXX), included requirements to control inorganic HAP emissions. These standards require confining all coating operations to a spray booth fitted with high efficiency filters, use of high transfer efficiency spray guns, and training and certification of spray equipment operator to optimize transfer efficiency.

We concluded that the controls for inorganic HAP emissions that were identified and required by these two area source NESHAP do not represent a development in practice, process or control technology that is applicable to metal can surface coating operations because the controls apply only to spray-applied coatings.

Organic HAP Emissions

The Metal Can NESHAP requires the use of add-on control technologies as an option to meet the emission limits above including an emission capture system, i.e., permanent total enclosure (PTE) used in conjunction with a thermal oxidizer, catalytic thermal oxidizer, regenerative thermal oxidizer (RTO), activated carbon adsorber, or a concentrator combined with an RTO. 

Subsequent technology reviews conducted as a part of the RTR process identified the following developments for the NESHAP identified in Table 1 above:

Printing and Publishing NESHAP (40 CFR 63 subpart KK): The technology review examined the option of retrofitting PTE onto those controlled presses that do not already have PTE. PTE improves the capture efficiency of solvent HAP from inks and delivers the additional captured solvent HAP to a control device. EPA estimated the cost-effectiveness of this retrofit to be over $50,000 per additional ton of HAP controlled, and therefore determined that the cost of this option would be disproportionate to the emission reduction that would be achieved. Thus, the EPA did not propose revising the existing printing and publishing MACT standards pursuant to section 112(d)(6) of the CAA to require a PTE. The use of a PTE was identified and considered during the Metal Can NESHAP development and is a control option for facilities choosing the emission rate with add-on control compliance option. Therefore, the controls for organic HAP emissions that were identified and required by the Printing and Publishing NESHAP do not represent developments in control technology or processes that are applicable to metal can surface coating operations.

Shipbuilding and Ship Repair NESHAP (40 CFR 63 subpart II): The technology review identified an add-on control device, a concentrator/RTO, that was recently installed (2009) at one shipbuilding and ship repair facility in California. The control device consisted of rotary concentrators followed by RTOs on five large, custom-built spray booths to control volatile organic emissions from the coating operations. The system is capable of achieving 95 percent control efficiency for the volatile organic HAP (VOHAP) emissions captured by the spray booths (which are estimated to capture 90 percent of the VOHAP emissions). However, the EPA concluded the use of this technology would only be practical and affordable at certain facilities building new ships and would not be affordable for facilities performing ship repair. The EPA estimated the cost-effectiveness of the concentrator/RTO system to be $305,000 per ton of VOHAP when used in ship building and repair. Given the significant differences between surface coating operations at ship building and repair facilities (includes spray application) and at can coating facilities (roll application), the results of the technology review for the Ship Building and Repair NESHAP are not applicable to the Metal Can surface coating operations.

Wood Furniture Manufacturing NESHAP (40 CFR 63 subpart JJ): The technology review identified the use of a RTO on a spray booth as a development for the coating of flat panels using an automated high-speed coating process. The technology review identified one facility using this control and fewer than five facilities that could install this technology. The technology review concluded that this technology was not cost effective for the facilities that were not currently using it.

In conclusion, the use of PTEs and RTOs was identified and considered during development of the Metal Can NESHAP as technologies capable of achieving an overall control efficiency of 95 percent and greater and is required, if needed, to meet the emission limits for new and existing sources. No new practices, processes or control technologies were identified in the Printing and Publishing, Shipbuilding or the Wood Furniture NESHAPs that were not considered during the Metal Can NESHAP development.

3.2.2	Improvements in Add-On Control Technology or Other Equipment for Organic HAP Emissions That Was Identified and Considered During MACT Development

The BACT determinations in the RBLC database that were made subsequent to promulgation of the Metal Can NESHAP specify the use of add-on controls, including PTE capture systems with a RTO and induction heater and catalytic oxidation. All of these control technologies were in use by the can coating industry during development of the Metal Can NESHAP and were already considered in the development of the Metal Can NESHAP. 

The technology review conducted for the Wood Furniture NESHAP identified the use of more efficient spray guns as a development and revised the requirements to prohibit the use of conventional spray guns. Air assisted airless spraying was added as a more efficient coating application technology. This development is not applicable to can coating because the primary coating operations are performed using non-spray application methods, such as lithographic printing and other types of direct transfer coating application, or they already use airless spray equipment for the inside spray, side seam spray, and repair coating operations. 

In conclusion, no improvements in add-on control technology or other equipment for organic HAP emissions were identified that were not already identified and considered during Metal Can NESHAP development

3.2.3	Work Practices and Procedures Not Identified and Considered During MACT Development

The current MACT standards require that, if a facility uses add-on controls to comply with the emission limitations, the facility must develop and implement a work practice plan 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. These work practices include the following:

 All organic-HAP-containing coatings, thinners, cleaning materials, and waste materials must be stored in closed containers.
 Spills of organic-HAP-containing coatings, thinners, cleaning materials, and waste materials must be minimized.
 Organic-HAP-containing coatings, thinners, cleaning materials, and waste materials must be conveyed from one location to another in closed containers or pipes.
 Mixing vessels which contain organic-HAP-containing coatings and other materials must be closed except when adding to, removing, or mixing the contents.
 Emissions of organic HAP must be minimized during cleaning of storage, mixing, and conveying equipment.

If a facility is not using add-on controls and is using either the compliant material option or the emission rate without add on controls option, the facility does not need to comply with work practice standards. Under the compliant material option, the materials covered by the work practices would be either non-HAP, or would already be compliant with numerical HAP content limits. Under the emission rate option, HAP emitted from spills or from containers would be counted against the facility in the compliance calculations, so facilities must already minimize these losses to maintain compliance. 

In conclusion, no additional work practices or procedures were identified that were not already identified and considered during MACT development. 

3.2.4	Any process change or pollution prevention alternative that could be broadly applied that was not identified and considered during MACT development.

Pollution prevention measures that are currently used by the industry and were considered during MACT development include product reformulations for coatings, including waterborne, higher solids, powder, and UV-curable finishes. Powder coatings are not currently applicable to the metal can coating process. Waterborne and higher solids coatings with lower HAP and VOC content were considered in the development of the proposed and final standards, and are reflected in the HAP emission limitations in the final rule. 

The development and use of BPA-NI, UV and EB coatings were discussed above in Section 2.3 in the context of the information provided in the American Coatings Association's market analysis. The EPA has not identified any developments in coating technology or other process changes or pollution prevention alternatives in the information reviewed that would represent a development relative to the coating technologies on which the final rule is based.

3.2.5 Any significant changes in the cost (including cost effectiveness) of applying controls   
         (including controls the EPA considered during the development of the original MACT
          standards).

As discussed above, a 97-percent (for a new or reconstructed source) and a 95-percent (for an existing source) overall control efficiency was determined to be the MACT floor for can coating sources. Most facilities had installed oxidizers to control emissions of VOC per NSPS (40 CFR Part 60 subpart WW) requirements prior to MACT development (see Table 4 for a more comprehensive breakdown of exiting controls). When developing the Metal Can NESHAP, the EPA estimated a cost effectiveness of approximately $8,300 to remove each ton of HAP. 

The information collected for this technology review has confirmed that the 5 major source facilities continue to comply with the NESHAP emission limits by using a combination of compliance options, including low- or no-HAP coatings and add-on capture and control systems. The EPA did not identify any developments in processes, practices or control technologies for the metal can source category as a result of this technology review. Therefore, we did not re-evaluate the cost (or cost-effectiveness) of applying additional add-on controls.  

