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MEMORANDUM

DATE:April 2022

SUBJECT:Best System of Emission Reduction (BSER) Review for Surface Coating of Plastic Parts for Business Machines (40 CFR Part 60, Subpart TTT) 

FROM:Eastern Research Group, Inc. (ERG)

TO:Lisa Sutton, OAQPS/SPPD/MMG


1.0INTRODUCTION

Section 111 of the CAA outlines the statutory requirements for the EPA's standards of performance for new stationary sources of pollutants, which are also known as the new source performance standards (NSPS). The EPA listed categories of sources in response to the 1970 CAA and promulgated NSPS for those categories in following years. The Surface Coating of Plastic Parts for Business Machines NSPS (40 CFR Part 60, Subpart TTT), hereafter referred to as the Business Machines NSPS, was promulgated on January 29, 1988. The Business Machines NSPS establishes standards of performance to limit emissions of volatile organic compound (VOC) emissions from new, modified, and reconstructed facilities that coat plastic parts of business machines and were based on the Administrator's determination that facilities that coat plastic parts of business machines contribute significantly to air pollution which may reasonably be anticipated to endanger public health or welfare. The intent of the NSPS is to require new, modified, and reconstructed business machine plastic parts coating operations to use the best demonstrated system of continuous emission reduction (BSER), considering costs, nonair quality health and environmental and energy impacts. 

CAA section 111(b)(1)(B) requires the EPA to "at least every 8 years review and, if appropriate, revise" new source performance standards. CAA section 111(a)(1) provides that performance standards are to "reflect the degree of emission limitation achievable through the application of the best system of emission reduction which (taking into account the cost of achieving such reduction and any nonair quality health and environmental impact and energy requirements) the Administrator determines has been adequately demonstrated." This level of control is referred to as the best system of emission reduction or "BSER." Because a review of the Business Machines NSPS has not been conducted in accordance this statutory obligation, EPA was recently sued, and the court-ordered deadline to propose review of the NSPS is June 1, 2022, and the deadline to take final action on the review of the NSPS is June 1, 2023. 

To comply with this CAA requirement, the EPA conducted a BSER review for the Business Machines NSPS. This memorandum addresses the BSER review for prime coating, color coating, texture coating, and touch-up coating processes, which from here forth will be referred to as NSPS surface coating operations. For this exercise, we consider any of the following to be a "development":

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

In addition to reviewing the practices, processes, and control technologies that were considered at the time EPA originally developed the NSPS, we reviewed a variety of data sources in our investigation of potential practices, processes, or controls to consider. Among the sources we reviewed were the documents supporting the 2004 Surface Coating of Plastic Parts and Products NESHAP, the 2020 RTR of the 2004 Surface Coating of Plastic Parts and Products NESHAP, the 1994 Alternative Control Techniques (ACT) Document for Surface Coating of Automotive/Transportation and Business Machine Plastic Parts, and the 2008 Control Techniques Guidelines (CTG) for Miscellaneous Metal and Plastic Parts Coatings. In addition, we performed a review of state operating permits for facilities subject to the Business Machines NSPS and a review of the EPA's RACT/BACT/LAER Clearinghouse database to identify more stringent emission limitations than the Business Machines NSPS as well as potentially new control technologies.

Section 2 of this memorandum presents a summary of the sources of data that were used to conduct the review and Section 3 presents the results of the review for the NSPS surface coating operations. 

Summary of BSER Development

During the development of the original standards, BSER (formerly referred to as Best Demonstrated Technology at the time the rule was developed, or BDT) was considered for both electromagnetic/radio frequency interference (EMI/RFI) shielding and exterior surface coating, while taking into consideration the cost of achieving such emission reduction and any nonair health and environmental impacts and energy requirements. The original BSER development discussed processes that provide EMI/RFI shielding to plastic parts for business machines. These processes include zinc-arc spray, zinc-flame spray, electroless plating, vacuum metallizing, sputtering, use of conductive plastics, and use of metal inserts. No BSER was proposed for EMI/RFI shielding, because the cost effectiveness of the EMI/RFI shielding options considered was unreasonable. The Business Machines NSPS does not regulate electromagnetic interference/radio frequency interference (EMI/RFI) shielding processes.

The BSER for exterior surface coating is a combination of coatings and application technologies: for prime and color coating this is the use of organic-solvent-based coatings containing approximately 60 percent, by volume, solids as applied and sprayed at a transfer efficiency (TE) of 40 percent; for fog coating this is the application of waterborne coatings at a TE of 25 percent; for texture and touch-up coating this is the application of organic solvent-based coatings containing approximately 60 percent solids at a TE of 25 percent. Waterborne coatings applied at a TE of 25 percent can also be used to meet the standards for prime, color, texture, and touch-up coating. 

The NSPS proposal projected an annual growth rate for the surface coating of plastic parts for business machines of 17 percent, which was considered high compared to that for other coating industries. The Business Machines NSPS promulgated in 1988 predicted that the standards would reduce the national VOC emissions in 1990 from an estimated 216 facilities that coat business machine plastic parts by about 2,200 megagrams (2,340 tons), or 51 percent of the total emissions from affected facilities. It was also predicted that the standard would reduce water pollution from water wash spray booths and reduce solid waste generated by a typical plant by approximately 25 percent. The standards created an insignificant impact on other environmental media such as noise, radiation, or energy impacts.

1.2Summary of Existing BSER Level of Control

The Business Machines NSPS promulgated in 1988 establishes the VOC emissions limits summarized in Table 1 for affected facilities (spray booths) that coat plastic business machine parts. 

Particular to the Business Machines NSPS, "coating solids applied" means the coating solids that adhere to the surface of the business machine plastic part being coated. 

Table 1. The Business Machines NSPS Emissions Limits for Affected Facilities (Monthly Average)

Coating Type
Limit
Prime coating
1.5 kg VOC/liter coating solids applied
Color coating
1.5 kg VOC/liter coating solids applied
Texture coating
2.3 kg VOC/liter coating solids applied
Touch-up coating
2.3 kg VOC/liter coating solids applied


The cost of controlling VOC emissions from ovens and flash-off areas with add-on controls was found to be unreasonable in the development of the original BSER standards, so the standard does not set operating limits for capture systems and add-on control devices. However, pursuant to 40 CFR 60.723(b)(2)(iv), facilities that use add-on controls and can demonstrate that the VOCs emitted to the atmosphere meet the applicable limits in the above table because of this equipment are in compliance. 
2.0SOURCES OF AVAILABLE CONTROL TECHNOLOGY INFORMATION

To identify any developments in practices, processes, or control technologies that could be applicable to the NSPS surface coating operations for facilities that coat business machine plastic parts, we consulted the following sources of data: the EPA's RACT/BACT/LAER Clearinghouse, regulatory actions promulgated subsequent to the Business Machines NSPS, regional and state regulations and operating permits, and industry information. 

2.1RACT/BACT/LAER Clearinghouse Database

Under the EPA's New Source Review (NSR) preconstruction permitting program, if a company is planning to build a new plant or modify an existing plant such that criteria air pollution emissions will increase by a certain amount, then the company must obtain an NSR permit. The NSR permit generally requires the company to minimize air pollution emissions through process controls to prevent air pollution and/or by 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) (nonattainment 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 nonattainment 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 database is not limited to sources subject to RACT, BACT, and LAER requirements. It also includes noteworthy prevention and control technology decisions and information even if they are not related to past RACT, BACT, or LAER decisions. 

The RBLC contains over 5,000 air pollution control permit determinations that can help identify appropriate technologies to mitigate most air pollutant emissions streams. It was designed to help permit applicants and reviewers make pollution prevention and control technology decisions for stationary air pollution sources, and it 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 online to locate applicable control technologies. We conducted a search of the RBLC processes specific to the "surface coating of plastic parts for business machines" category of permits dating back to 2000. The search results included the following data fields:
 
      RBLC ID;
      Facility Name, and State;
      Permit Date;
      Process name;
      Pollutant;
      Control technology; 
      Percent efficiency of control;
      Emissions limits
      Control and process notes.

      In a 2021 search, we identified one RBLC entry representing a single facility with the "Plastic Parts for Business Machines Surface Coating" process type, i.e., Douglas Corporation in Minnesota. The facility is a manufacturer of plastic product identifiers, including nameplates, decals, and decorative trim. Its clients primarily include automobile and large equipment manufacturers. This facility continues operations today under a different name, Aludec USA. Subpart TTT is included in the facility's air permit, but this facility has never coated plastic parts for business machines.
      
      The facility was modified several times without first obtaining the appropriate permits. As part of a stipulation agreement, this facility was required to apply BACT for VOC where pollution prevention requirements were incorporated into the 2001 permit:
Commit to research waterborne coatings and apply them where feasible, 
Avoid the use of Methyl Ethyl Ketone in paint thinners and/or clean up solvents, 
Use high-volume, low-pressure (HVLP) spray guns for all non-finish coating operations and achieve 75 percent transfer efficiency for all spray guns. 

Developments identified in the RBLC listed above will be discussed in Section 3 (BSER Review for Surface Coating Operations).
 
2.2Subsequent Regulatory Actions

Regulatory actions promulgated subsequent to the January 29, 1988, Business Machines NSPS have been identified for sources similar to business machine plastic parts surface coating operations. These regulatory actions were reviewed for developments in practices, processes, and control technologies.

The first of these regulatory actions is the Surface Coating of Plastic Parts and Products NESHAP (40 CFR Part 63, Subpart PPPP) ("Plastic Parts NESHAP"), promulgated on April 19, 2004 (69 FR 20968). The Plastic Parts NESHAP establishes emission standards for plastic parts and products surface coating operations located at major sources of hazardous air pollutants (HAP); it does not regulate area sources. The regulated facilities for the Plastic Parts NESHAP are those engaged in the surface coating of parts including: motor vehicle parts and accessories for automobiles, trucks, recreational vehicles; sporting and recreational goods; toys; business machines; laboratory and medical equipment; and household and other consumer products. The NESHAP requires sources to meet standards that reflect the use of maximum achievable control technology (MACT) to reduce HAP emissions from the following operations: surface preparation; equipment cleaning; coating mixing; coating storage; and waste handling. The Plastic Parts NESHAP provides emission limits in terms of mass of organic HAP emitted per mass of coating solids used, and facilities may comply by applying coatings that meet the limitations, or by using an emission capture system and control device. For sources that use a capture system and control device to comply with the Plastic Parts NESHAP, the rule requires the development and implementation of a work practice plan to minimize organic HAP emissions.

The second of these actions is the 2020 risk and technology review (RTR) of the 2004 Plastic Parts NESHAP, promulgated on July 8, 2020. The 2020 RTR identified developments in surface coating technology and practices, including advancements in coating spray gun efficiency and coating reformulation options. These developments are discussed in detail in section 3.

The third and fourth actions were the 1994 ACT Document for Surface Coating of Automotive/Transportation and Business Machine Plastic Parts and the 2008 CTG for Miscellaneous Metal and Plastic Parts. Both the 1994 ACT and the 2008 CTG are intended to provide State and local authorities with information that can be used to develop Reasonably Available Control Technology (RACT)-based emission limits for VOCs. The 1994 ACT provides VOC control options (two levels) based on the VOC content of low-VOC coatings but does not specify RACT emission limits. See Table 2. In addition to recommending RACT VOC content limits in the format of mass of VOC per unit volume of coating, less water and exempt compounds, as applied, the 2008 CTG separately expressed those recommended VOC emission limits in the format of mass of VOC per unit volume of coating solids, for sources that use a combination of low-VOC coatings and emission capture systems and control devices. See Table 3. The VOC content limits and emission limits for surface coating of plastic parts for business machines are shown in the tables below. 

Although the Business Machines NSPS does not regulate EMI/RFI shielding processes, the 1994 ACT recommended a control level of 4.0 lb of VOC per gallon of coating (0.48 kg of VOC per liter of coating), less water and exempt solvents, for EMI/RFI shielding coatings. 

Table 2. Recommended VOC content limits for surface coating of business machine plastic parts from the 1994 ACT for Surface Coating of Automotive/Transportation and Business Machine Plastic Parts


1994 ACT recommended VOC content limits
Category
Coating type
kg VOC/l coating, less water and exempt solvents a 
(lb VOC/gal)

kg VOC/l coating solids applied b
(lb VOC/gal)

Level 1
Level 2
Level 1
Level 2
Business Machines
Color Coat
3.5
2.3
2.0
1.0
Color Coat/Texture Coat
3.5
2.3
2.0
1.0
Primer
2.9
1.2
1.8
0.43
EMI/RFI Shielding
4.0
4.0
2.6
2.6
    a The 1994 ACT reformulation limits are specified in Table 4-1 (page 134 of 207).
    b An assumed VOC density of 0.88 kg/l is necessary to convert the coating VOC concentration from "kg VOC/liter coating less water and exempt solvents" to "kg VOC/liter coating solids." An assumed transfer efficiency of 0.40 is necessary to convert the coating concentration from kg VOC/liter coating solids to kg VOC/liter coating solids applied.

Table 3. Recommended VOC content limits for surface coating of business machine plastic parts from the 2008 CTG for Miscellaneous Metal and Plastic Parts Coatings


2008 CTG recommended VOC content limits
Coating type
 kg VOC/l coating solids
(lb VOC/gal)a
kg VOC/l coating solids applied b
(lb VOC/gal)
Business Machines Coatings
Primers
4.8
1.4
Topcoat
4.8
1.4
Texture Coat
4.8
1.4
Fog Coat
3.2
0.95
Touchup and Repair
4.8
1.4
    a The 2008 CTG limits are specified in Table 9 (page 43 of 142). The same limits, expressed as lb VOC/gal coating, less water and exempt compounds, as applied, are specified in Table 4.
    b These limits have been converted to kg of VOC per liter of coating solids deposited by assuming a 40 percent transfer efficiency.


The 2008 CTG recommends emissions limits for general plastic parts and products (10 coating categories), business machine coatings (5 categories), and automotive and transportation coatings (11 coating categories). The 2008 CTG recommendations were based on the California South Coast Air Quality Management District Rule 1145 (February 14, 1997) for Plastic, Rubber, Leather, And Glass Coatings, and Michigan Rule 336.1632 (as amended April 28, 1993) for Emission of Volatile Organic Compounds from Existing Automobile, Truck, And Business Machine Plastic Part Coating Lines.  

The 2008 CTG provides recommendations for multiple VOC emission control options:
VOC content limits based on the use of low-VOC coatings, with limits given in mass VOC per volume of coating (excluding water and exempt compounds, as applied);
VOC emission limits based on the use of low-VOC coatings and add-on controls, with limits given in mass VOC per volume of coating solids, as applied;
For facilities that coat products with performance or other requirements that dictate the use of higher-VOC coatings, the use of add-on control equipment (such as oxidizers, adsorbers, absorbers, or concentrators) with an overall control efficiency of at least 90 percent in lieu of using low-VOC coatings and specified application methods;
Work practices for coating-related activities and for cleaning materials; and
The use of high-efficiency coating application methods.

The 2008 CTG did not recommend a VOC limit for EMI/RFI shielding coatings, but it recommended that the recommended application methods and work practices apply to those coating operations.

The Business Machines NSPS VOC emission limits (shown in Table 1) are expressed in units of kg of VOC per liter of coating solids deposited, while the 1994 ACT limits are expressed in mass of VOC per volume of coating, less water and exempt solvents and the CTG limits are expressed as mass of VOC per volume of coating solids. Therefore, the limits cannot be directly compared without assuming a transfer efficiency for the application equipment. Based on a transfer efficiency of 40 percent, the VOC content limits in the Business Machines NSPS are less stringent than the content limits in both the 1994 ACT (at level 2) and the 2008 CTG (excepting the ACT's EMI/RFI shielding coating category). Overall, the limits given in the 2008 CTG are less stringent than the limits given in the 1994 ACT.

2.3 State VOC Rules

As part of this BSER review, we researched state VOC rules that were developed in response to 1994 ACT and 2008 CTG developed by EPA to limit VOC emissions. 

In 1994, EPA published an ACT for VOC emissions from surface coating of automotive and other transportation sector plastic parts and business machine plastic parts. In 2008, EPA issued a CTG for VOC from miscellaneous metal and plastic parts coating. According to the 2008 CTG, at least 13 States had emission limits for coating lines that are specifically for plastic parts and products. Seven of the State rules (Delaware, Illinois, Massachusetts, Michigan, New Hampshire, Tennessee, and Wisconsin) were specifically for business machine plastic parts and followed the categories and control levels included in the 1994 ACT for these categories. The other six states (Arizona, California, Indiana, Maryland, Missouri, and New York) had not adopted the control levels provided in the 1994 ACT. Instead, they had adopted limits for only one or two categories of plastic parts coatings. In some cases, these limits applied to all plastic parts coatings and were not limited to only business machine plastic parts. These limits were generally not as stringent as the most stringent control level in the 1994 ACT for comparable coating categories. Three California Air Quality Management Districts (Antelope Valley AQMD, Bay Area AQMD, and South Coast AQMD) had rules containing emission limits for coating plastic parts. 

The 2008 CTG recommends emissions limits for general plastic parts and products (10 coating categories) and business machine coatings (5 categories). The 2008 CTG recommendations were based on the California South Coast Air Quality Management District Rule 1145 (February 14, 1997) for Plastic, Rubber, Leather, And Glass Coatings, and Michigan Rule 336.1632 (as amended April 28, 1993) for Emission of Volatile Organic Compounds from Existing Automobile, Truck, And Business Machine Plastic Part Coating Lines.  

At least nine states (New York, Missouri, Maryland, Indiana, California, New Hampshire, Michigan, Massachusetts, and Ohio) have adopted regulations with VOC content limits equal to those set forth in the 2008 CTG for surface coating of plastic parts for business machines. All of these state rules limit VOCs to levels below what is required by the Business Machines NSPS.

California has a total of thirty-four Air Quality Management Districts (AQMD), and we examined the district rules for plastic parts surface coating operations in six of those districts: Antelope Valley, Bay Area, Eastern Kern County, Placer County, South Coast, and San Joaquin Valley. Of these districts, only two specifically regulate surface coating of plastic parts of business machines (Eastern Kern County and San Joaquin Valley); the other four districts regulate plastic parts surface coating operations more generally, but the rules may still cover plastic parts of business machines.

Antelope Valley AQMD Rule 1145 predates the Business Machines NSPS as it was adopted in 1983 and last amended in 1997. It established VOC content limits for coatings and requirements to use high-efficiency application methods. Compliance could be demonstrated by compliant coatings or by using a control device with at least 90 percent collection efficiency and at least 95 percent destruction efficiency or an outlet VOC concentration of less than 50 ppm as carbon. Solvent cleaning operations and the storage and disposal of VOC containing materials are subject to the provisions of AVAQMD Rule 1171 - Solvent Cleaning Operations. This rule does not have provisions specific to plastic parts of business machines, but the rule text states that its purpose is to reduce VOC emissions "from the application of coatings to any plastic, rubber or glass products." Therefore, this regulation should apply to surface coating of plastic parts of business machines.

Bay Area AQMD Rule 8-31 also predates the Business Machines NSPS as it was adopted in 1983 and last amended in 2002. It established VOC content limits for coatings and requirements to use high-efficiency application methods, and work practice requirements for solvents for equipment cleaning and surface preparation. Compliance could also be demonstrated by using a control device with at least 85 percent overall capture and control efficiency. This rule does not have provisions specific to plastic parts of business machines, but the rule text states that its purpose is to limit VOC emissions "from the surface preparation and coating of plastic parts and products, including polyester resin (fiberglass) products." Therefore, this regulation should apply to surface coating of plastic parts of business machines.

Eastern Kern APCD Rule 410.4 predates the Business Machines NSPS as it was adopted in 1979 and was most recently amended in 2014. It established VOC content limits for coatings and requirements to use high-efficiency application methods. Compliance could also be demonstrated by using a control device with at least 90 percent capture efficiency and 90 percent control efficiency. The rule established solvent VOC content and vapor pressure limits, and work practice requirements for solvents for equipment cleaning and surface preparation. This rule specifically regulates surface coating of plastic parts of business machines, including VOC content limits for business machine plastic parts and products coatings. The VOC content limits for business machine plastic parts and products coatings match the limits set forth in the 2008 CTG (see Table 3).

Placer County APCD Rule 249 was adopted in 2013. It established VOC content limits for coatings. Compliance with the VOC content limits could also be demonstrated by using a control device with at least 90 percent overall capture and control efficiency. The rule required the use of high-efficiency application methods. The rule established solvent VOC content limits for solvents used for stripping coatings, application equipment cleaning, and surface preparation. The rule established work practice requirements for all VOC containing materials. This rule does not have provisions specific to plastic parts of business machines, but the rule text states that its purpose is to limit VOC emissions "from the application of coatings, coating removers (strippers), surface preparation materials, and cleanup materials in plastic parts and products coating operations." Therefore, this regulation should apply to surface coating of plastic parts of business machines.

South Coast AQMD's Rule 1145 predates the Business Machines NSPS as it was adopted in 1983 and was last amended in 2009. It established VOC content limits for coatings and requirements to use high-efficiency application methods. Solvent cleaning operations and the storage and disposal of VOC containing materials are subject to the provisions of SCAQMD Rule 1171 - Solvent Cleaning Operations. Compliance could also be demonstrated by using a control device with at least 90 percent collection efficiency and at least 95 percent destruction efficiency or an outlet VOC concentration of less than 50 ppm as carbon. This rule does not have provisions specific to plastic parts of business machines, but the rule text states that its purpose is to reduce VOC emissions "from the application of coatings to any plastic, rubber, leather, or glass products." Therefore, this regulation should apply to surface coating of plastic parts of business machines.

San Joaquin Valley Unified APCD Rule 4603 was adopted in 1991 and last amended in 2009. It established VOC content limits for coatings and for solvents used for application equipment cleaning and surface preparation. The rule established requirements to use high-efficiency coating application methods. Compliance with the VOC content limits for coatings and cleaning solvents and the coating application methods could also be demonstrated by using a control device with at least 90 percent overall capture and control efficiency. The rule established work practice requirements for all VOC containing materials. This rule specifically regulates surface coating of plastic parts of business machines, including VOC content limits for business machine plastic parts and products coatings. The VOC content limits for business machine plastic parts and products coatings match the limits set forth in the 2008 CTG (see Table 3).

The VOC content limits in the California district rules for plastic parts surface coating generally translate into lower VOC content limits than the limits in the business machines NSPS. The Business Machines NSPS VOC emission limits are expressed in units of kg of VOC per liter of coating solids deposited, while most of the California district limits are expressed in VOC per volume of coating, less water and exempt compounds. Therefore, the limits cannot be directly compared without assuming a transfer efficiency for the application equipment. Based on a transfer efficiency of 40 percent, the VOC content limits in the Business Machines NSPS are less stringent than the content limits in Eastern Kern APCD and San Joaquin Valley Unified APCD, both of which have limits matching those recommended in the 2008 CTG. Three of the other districts (Antelope Valley AQMD, Placer County APCD, and South Coast AQMD) list different types of coatings than those listed in the NSPS, but the least stringent limit listed in each of these rules is more stringent than the least stringent limit listed in the NSPS. The remaining district, Bay Area AQMD, lists its VOC content limits in terms of kg VOC per liter of coating less water, which is not comparable to the VOC content limits in the NSPS. We have not been able to confirm whether any facilities are actually complying with these more stringent limits.

In summary, there are currently at least 13 States whose rules limit VOC emissions from surface coating of plastic parts of business machines that are more stringent than the current Business Machines NSPS. Within California, at least five California air districts have VOC emission limitation rules that are more stringent than the Business Machines NSPS, some of which are specific to business machines, and some of which are more general limitations for plastic parts surface coating. 

2.4 State Operating Permits

State operating permits were also reviewed to find information about VOC emission limitations and developments in control technology. EPA identified 17 facilities in its Enforcement and Compliance History Online (ECHO) database as subject to the Business Machines NSPS and was able to gather information about these facilities from state operating permits and discussions with state regulators. Of the 17 facilities, nine had permit documents indicating that they were subject to the NSPS at the time of review, five facilities had permits that did not discuss applicability to the Business Machines NSPS, one facility's permit stated that it is not subject to the NSPS, and one facility had emissions that were too low to require a permit. There was one facility for which EPA did not locate a permit, but a state regulator informed EPA that the facility is no longer subject to the NSPS. Three of the nine permits that indicated the facility was subject to the Business Machines NSPS had VOC emission limits more stringent than the NSPS. 

Upon contacting these nine individual sources we learned that only three of those sources currently perform surface coating of plastic parts for business machines. 

2.5 Site Visits

Due to the ongoing COVID-19 pandemic and other government travel restrictions no sites were visited as of April 2022. 

2.6 Industry Information

As part of this BSER review, paint manufacturer Sherwin-Williams and the American Coatings Association were contacted. They explained that the domestic application of surface coating applied to business machines since the NSPS was promulgated has declined. Much of manufacturing has moved outside of the US. Further, in the 1980's, the quality of extruded parts was lower, and coatings were used to cover up imperfections and surface defects. Plastic parts are now commonly molded in the end color. To better understand the facility operations, we contacted each of the nine facilities that had permit documents indicating that they were subject to the NSPS.

Most of this coating application is done at job shops (i.e., not the original equipment manufacturer). Job shops are typically small manufacturing systems that handle job production such as small- to medium-size customer orders or batch jobs. Job shops typically move on to different jobs when each job is completed. These job shops are not specialized to businesses equipment coatings; they may be specialized to plastic parts but likely are coating multiple materials (e.g., metal, plastic). Typically, these facilities have the Subpart TTT regulations in the permit but report no Subpart TTT activity to State regulators. Surface coating is typically applied to medical equipment, game consoles, consumer electronics, and appliances. Customers specify the type of paint they want used. 

Among facilities that are permitted for Subpart TTT activity but are not currently engaged in surface coating of plastic parts for business machines is Mack Molding in Statesville NC. That job shop estimated they applied surface coating for 25 different customers, including E-Z-GO golf carts and Sensormatic. The facility experimented with robotic coating application but removed it because of their short product runs and required time to reset the robot. For instance, they might paint one part for 3 hours then another for 6 hours. Mack Molding indicated that VOC restrictions are not an operational limitation, but when asked how a new facility might be different they indicated an afterburner would be considered to control VOC emissions because of the additional flexibility, with respect to compliance with permit limits. Specifically, controlled VOC emissions could allow for higher production and more variability in coating VOC content. 

A second cohort of facilities permitted to coat plastic parts for business machines is remanufacturers, and a single facility was identified. Xerox remanufactures Xerox products, which involves making exterior panels look new again by repainting them. One of the products Xerox remanufactures is the multifunction machine Nuvera. A print shop might use this large machine, a digital press, to produce magazines or mailers. These remanufactured products are high-value and with cosmetic repairs can be resold. No other high-value original equipment manufacturers (e.g., HP, IBM, Lexmark) were identified. It is unclear if these corporations use parts manufactures that operate outside the US or if they use job shops. 

3.0BSER REVIEW FOR SURFACE COATING OPERATIONS

The Business Machines NSPS covers each spray booth in which plastic parts of business machines receive prime coats, color coats, texture coats, or touch-up coats. A business machine is defined in the NSPS as "a device that uses electronic or mechanical methods to process information, perform calculations, print or copy information, or convert sound into electrical impulses for transmission, such as: 
Products classified as typewriters under SIC Code 3572;
Products classified as electronic computing devices under SIC Code 3573;
Products classified as calculating and accounting machines under SIC Code 3574;
Products classified as telephone and telegraph equipment under SIC Code 3661;
Products classified as office machines, not elsewhere classified, under SIC Code 3579; and
Photocopy machines, a subcategory of products classified as photographic equipment under SIC code 3861."

The NSPS defines a coating operation as the use of a spray booth to apply a single type of coating; if the same spray booth is used to apply more than one type of coating, each coating type constitutes a separate coating operation for purposes of compliance determinations. Prime coat is defined in the Business Machines NSPS as the initial coat applied to a part when more than one coating is applied. Color coat is defined as a coat, other than a prime or texture coat, that is applied to a part that affects the color and gloss of the part, including fog coating. Fog coating is defined as a thin coating applied to plastic parts that have molded-in color, texture, or both to improve color uniformity. Texture coat is defined as a rough coat that is characterized by discrete, raised spots on the exterior surface of the part. Touch-up coat is defined as a coat applied to correct imperfections in the finish following application of color or texture coats. The coating types covered by the Business Machines NSPS do not include conductive sensitizers or electromagnetic interference/radio frequency interference (EMI/RFI) shielding coatings. The Business Machines NSPS only applies to spray booths and does not cover other coating application methods. The regulated pollutant emitted by these processes is VOC.

The emission limits in the Business Machines NSPS cover all VOC emissions that are caused by the coatings applied in each subject spray booth, regardless of the point of discharge to the atmosphere. The VOC emission sources in these coating operations are the spray booths, flash-off areas, and curing ovens. 

3.1Identified Control Measures for Surface Coating Operations

As presented above in sections 2.1, 2.2, 2.3, and 2.4, potential developments in practices, processes, and control technologies were identified in the RBLC data, regulatory actions promulgated after the Business Machines NSPS, and state operating permits. Each potential development is examined below.

3.1.1Add-On Control Technology or Other Equipment Not Identified and Considered During BSER Development

Particulate Matter (PM) Emissions:
PM emissions were not considered in the development of the Business Machines NSPS. PM would have the potential to be emitted when coatings are spray-applied, but the PM would be either deposited on the part being coated as part of the surface coating, on the walls and floors of the spray booth, or captured by the spray booth filters (typically either a dry fabric filter or a water wash filter system). 

VOC Emissions:
The RBLC search, conducted in October 2021, identified one facility with the "Plastic Parts for Business Machines Surface Coating" process type. As noted in section 2.1, the facility is a manufacturer of plastic product identifiers, including nameplates, decals, and decorative trim. Its clients primarily include automobile and large equipment manufacturers. The facility was modified several times without first obtaining the appropriate permits. As part of a stipulation agreement, this facility was required to apply BACT for VOC where pollution prevention requirements were incorporated into the permit:
Change to non-VOC materials for all paint thinner and cleaning operations, 
Commit to research waterborne coatings and apply them where feasible, 
Avoid the use of Methyl Ethyl Ketone (MEK) in paint thinners and/or clean up solvents. 
Waterborne coatings were identified and considered during BSER development for the Business Machines NSPS, but the other stipulations listed above were not. 

3.1.2Improvements in Add-On Control Technology or Other Equipment for VOC Emissions That Was Identified and Considered During BSER Development

During the determination of BSER for the 1988 NSPS, the main developments that were considered and identified were the transition to waterborne from solvent-borne coatings and the use of air-assisted airless or electrostatic spray coating. The Business Machines NSPS lists an expected transfer efficiency of 0.40 for air-assisted airless spray and electrostatic spray and an expected transfer efficiency of 0.25 for conventional air atomized spray.

The EPA's 2008 CTG for Miscellaneous Metal and Plastic Parts Coatings states that electrostatic spray transfer efficiency typically ranges from 0.60 to 0.90, while conventional air atomized spray transfer efficiency typically ranges from 0.25 to 0.40. The 2008 CTG does not provide an estimate of transfer efficiency for air-assisted airless spray, but in the 2010 technology review conducted for the Wood Furniture Manufacturing Industry, the EPA found that air-assisted airless spray guns can have transfer efficiencies as high as 0.65 and as low as 0.50. 

It should be noted that TE is dependent not only on the type of application method, but performance can vary according to the shape and size of coated items and the technique and skill of the operator. Wagner Industrial Solutions has stated the following: 

    For facilities who only need to paint a single part style, the spray gun can be set up so that it is perfectly optimized. However, many manufacturers will produce a wide range of parts (and some custom coaters never paint the same part style twice). Where there is a wide range of parts, and paints that must be accommodated, a more "forgiving" spray technology should be selected.

There are differences in achievable TE even within a single spray application method. Factors that influence TE can include operator variability, equipment characteristics (e.g., fluid and air pressure), and air conditions in the spray booth (e.g., humidity, temperature, air velocity). The range of TE values in EPA regulations illustrate this variance within a given coating application method. See examples in Table 4.

Table 4. Surface Coating Regulatory Standards, Transfer Efficiencies 

Regulatory Standard
Application Technology

Air-atomized spray
Manual Electrostatic Spray
NSPS  -  Subpart MM; Standards of Performance for Automobile and Light Duty Truck Surface Coating Operations a
Waterborne coating: 0.39

Solvent-borne coating 0.50
0.75
NSPS  -  Subpart SS; Standards of Performance for Industrial Surface Coating: Large Appliances
0.40
0.60
    a Transfer efficiency represent an overall system efficiency which include a total capture of purge. Alternate values are available if a spray system uses line purging after each vehicle and does not collect any of the purge material. 

Spray guns operate under the basic principle of forcing paint out a nozzle and mixing it with air to atomize the paint material. Adding a negative electric charge to atomized paint creates an electrostatic air spray where charged paint particles seek a grounded workpiece, like metal wire or metal appliance. Electrostatic spraying can be done on nonconductive plastic parts, but a conductive primer or conductive adhesion promoter must be applied first. 

The use of a permanent total enclosure (PTE) in conjunction with a thermal oxidizer, catalytic thermal oxidizer, regenerative thermal oxidizer (RTO), activated carbon adsorber, or a concentrator combined with an RTO was considered during development of the Plastic Parts NESHAP. The Plastic Parts NESHAP includes a compliance option involving the use of a PTE and an add-on control for limiting organic HAP emissions, and the NESHAP provides specific operating limits for add-on controls. Enclosures with add-on controls can also be used to limit VOC emissions, and such options were evaluated during BSER development for the Business Machines NSPS. These control options were determined to be unreasonable for the control of VOC emissions from spray booths, flash-off areas, and ovens due to the costs associated with supplemental fuel and building enclosures for flash-off areas. At the time of BSER development add-on controls were not used in this industry, and based on available information, no facilities have adopted the use of these add-on controls. Operating limits for add-on controls are not included in the Business Machines NSPS, but the NSPS allows for the use of add-on controls as an option to reduce VOC emissions to the required limits. Since these options were already considered, they do not represent a development in control technology for the Business Machines NSPS.

3.1.3Surface Coating Materials Not Identified and Considered During BSER Development

The use of paint strippers, paint thinners, and other cleaning materials was not considered during the BSER development for the Business Machines NSPS. According to the 2008 CTG, cleaning materials are frequently used at coating facilities to clean equipment such as spray guns, spray booths, transfer lines, and tanks, and these materials are typically mixtures of VOC-containing solvents. While coatings are the main source of VOCs from coating operations, cleaning materials are another significant source, and VOCs are emitted when solvents evaporate from the cleaning materials during use. The CTG recommends specific work practice procedures for reducing emissions from cleaning operations: 
Cover mixing and storage vessels for VOC-containing cleaning materials and cleaning waste materials, except when adding, removing, or mixing contents;
Use closed containers or pipes to store and convey VOC-containing cleaning and cleaning waste materials;
Minimize spills of VOC-containing cleaning and cleaning waste materials; and 
Minimize VOC emissions during cleaning operations.

VOC emissions from cleaning materials may also be reduced by using alternative products with low-VOC content or a low-VOC composite vapor pressure. However, the 2008 CTG acknowledges that these alternative products may not be feasible for all coating types. The CTG does not recommend the use of a VOC content limit or VOC composite vapor pressure limit for cleaning materials because information was not available on those metrics for cleaning materials used in relevant operations at the time of development. The CTG also does not recommend the use of add-on controls to reduce emissions from cleaning operations due to their high cost.

The Plastic Parts NESHAP limits organic HAP emissions from coatings, cleaning materials, and paint thinners and other additives. Facilities may meet emission limits for the Plastic Parts NESHAP using one of three methods: (1) a compliant material option, where all coatings used have organic HAP contents that individually meet the organic HAP emission limit, and all thinners, additives, and cleaning materials contain no organic HAP; (2) an emission rate without add-on controls option, where the average rolling 12-month organic HAP emission rate for all coatings, thinners, additives, and cleaning materials is equal to or less than the organic HAP emission limit; or (3) an emission rate with add-on controls option, where the rolling 12-month emission rate, taking into account the emission reduction achieved through the use of emission capture systems and add-on controls, is equal to or less than the organic HAP emission limit. Since this NESHAP is based on reformulation to lower the HAP content of coatings, cleaning materials, and thinners, it is not known how compliance has affected VOC emissions given that HAP could be replaced with non-HAP VOC.

Rules from the six California air districts discussed in section 2.3 were also reviewed to determine whether they control emissions from coating materials not identified in the BSER development for the Business Machines NSPS.

Antelope Valley AQMD Rule 1145 does not regulate VOC-containing materials other than coatings. However, Antelope Valley AQMD has a separate rule for solvent cleaning operations, Rule 1171, which was adopted in 1991 and last amended in 2018. It established VOC content limits for cleaning solvents and restricted the use of solvents containing certain compounds. The rule established requirements for specific cleaning devices, methods, and work practices. Compliance could also be demonstrated by using a control device with at least 90 percent collection efficiency and at least 95 percent destruction efficiency or an outlet VOC concentration of less than 50 ppm as carbon. The rule regulated all solvent cleaning operations that used VOC-containing materials "during the production, repair, maintenance, or servicing of parts, products, tools, machinery, equipment, or general work areas," and storage and disposal of VOC-containing materials used in solvent cleaning operations. The definition of Solvent Cleaning for this rule included the removal of uncured adhesives, inks, coatings, and contaminants and does not apply to cured coatings (i.e., coatings that are dry to the touch). This rule does not have provisions specific to plastic parts of business machines, but the regulated operations are likely to occur at facilities that surface coat plastic parts of business machines.

As discussed in section 2.3, Bay Area AQMD Rule 8-31 was adopted in 1983 and last amended in 2002. It established VOC content limits for coatings as well as work practice requirements to limit evaporative losses from solvents used for equipment cleaning and surface preparation. Regulated solvents included: catalysts or thinners; those used to clean plastic parts prior to coating, further treatment, sale, or intended use; and those used for cleanup or mixing of coatings. The work practice requirements for organic solvents included use of closed containers for storage or disposal and restrictions on the use of organic solvents for cleanup of spray equipment. Compliance could also be demonstrated by using a control device with at least 85 percent overall capture and control efficiency. This rule does not have provisions specific to plastic parts of business machines, but the surface preparation operations that are regulated by the rule are likely to occur at facilities that surface coat plastic parts of business machines.

As discussed in section 2.3, Eastern Kern APCD Rule 410.4 was adopted in 1979 and last amended in 2014. The rule established VOC content and vapor pressure limits for solvents used for surface preparation and cleaning of coating application equipment, as well as work practice requirements including specific cleaning devices and methods. Compliance with the rule's VOC content limits for surface preparation solvents could also be demonstrated by using a control device with at least 90 percent capture efficiency and 90 percent control efficiency. This rule specifically regulates surface coating operations for plastic parts of business machines and the cleaning, storage, and disposal of solvents associated with those operations. 

As discussed in section 2.3, Placer County APCD Rule 249 was adopted in 2013. The rule established solvent VOC content limits for solvents used for stripping coatings, application equipment cleaning, and surface preparation. The rule established work practice requirements for all VOC-containing materials, including minimizing spillage and using closed containers for disposal and storage. This rule does not have provisions specific to plastic parts of business machines, but the regulated operations are likely to occur at facilities that surface coat plastic parts of business machines.

South Coast AQMD Rule 1145 does not regulate VOC-containing materials other than coatings. However, South Coast AQMD has a separate rule for solvent cleaning operations, Rule 1171, which was adopted in 1991 and last amended in 2009. It established VOC content limits for cleaning solvents and requirements for specific cleaning devices, methods, and storage practices. Compliance could also be demonstrated by using a control device with at least 90 percent collection efficiency and at least 95 percent destruction efficiency or an outlet VOC concentration of less than 50 ppm as carbon. The rule regulated all solvent cleaning operations that used VOC-containing materials "during the production, repair, maintenance, or servicing of parts, products, tools, machinery, equipment, or general work areas," and storage and disposal of VOC-containing materials used in solvent cleaning operations. The definition of Solvent Cleaning for this rule included the removal of uncured adhesives, inks, coatings, and contaminants and does not apply to cured coatings. This rule does not have provisions specific to plastic parts of business machines, but the regulated operations are likely to occur at facilities that surface coat plastic parts of business machines.

As discussed in section 2.3, San Joaquin Valley Unified APCD Rule 4603 was adopted in 1991 and last amended in 2009. It established VOC content limits for solvents used for application equipment cleaning and surface preparation, including fresh or spent solvents, waste solvent cleaning materials, and thinners. The rule did not apply to stripping of cured coatings, except from spray application equipment. Compliance with the VOC content limits could also be demonstrated by using a control device with at least 90 percent overall capture and control efficiency. The rule established work practice requirements for all VOC-containing materials, including storing materials in closed containers, closing mixing vessels when not in use, minimizing spills, and conveying materials in closed containers or pipes. This rule specifically regulates surface coating operations for plastic parts of business machines and the cleaning, storage, and disposal of solvents associated with those operations.

The EPA reviewed VOC regulations from the nine states identified in section 2.3 as having VOC content limits equal to those set forth in the 2008 CTG for surface coating of plastic parts of business machines. Of these states, seven states (New York, Missouri, Indiana, California, New Hampshire, Massachusetts, and Ohio) have rules that regulate VOC-containing materials such as cleaning materials, coating thinners, and coating-related waste materials at facilities that surface coat plastic parts of business machines. The regulations include work practice requirements for handling and use of these materials, such as the use of closed containers for storage, specific methods for cleaning spray equipment while minimizing VOC emissions, minimizing spills of VOC-containing materials, and use of closed pipes or containers for conveying VOC-containing materials. The Massachusetts rule also included VOC content limits for cleaning solvents used at facilities that surface coat plastic parts of business machines. Michigan and Maryland did not have rules that regulate VOC-containing materials other than coatings at facilities that surface coat plastic parts of business machines.

The 1988 NSPS defined its "affected facility" to be the spray booth. The VOC-containing materials such as cleaning materials, coating thinners, and coating-related waste materials are outside the scope of the NSPS. Further, these other materials were not considered as BSER because they are not part of the "affected facility."

3.1.4Work Practices and Procedures Not Identified and Considered During BSER Development

During the original BSER and Business Machines NSPS development, no work practices to minimize VOC emissions were included in the NSPS. However, the 2004 Plastic Parts NESHAP requires affected sources to 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, all coating operations for which emission limits are established if a facility is using the emission rate with add-on controls compliance option..

The work practice plan required by the 2004 Plastic Parts NESHAP must specify practices and procedures to ensure the following:
All organic-HAP-containing coatings, thinners, cleaning materials, and waste materials must be stored in closed containers. 
The risk of 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, other than day tanks equipped with continuous agitation systems, 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.

Additionally, several states have adopted regulations with work practice requirements for handling of VOC-containing coatings and other materials, as described in section 3.1.3 of this memorandum. Xerox Corporation's active air permit includes common work and operational practices that impact activities other than the spray booth, such as solvent transfer and storage. 

Work practices and procedures that impact activities other than the spray booth were not considered as BSER because they are not part of the "affected facility."

3.1.5Any process change or pollution prevention alternative that could be broadly applied but was not identified and considered during BSER development.

As noted in section 2.1, one facility with the "Plastic Parts for Business Machines Surface Coating" process type was identified in the RBLC. This facility, Aludec USA, was required to apply BACT for VOC, and high-volume, low-pressure (HVLP) spray guns were required for all non-finish coating operations. Further, 75 percent transfer efficiency shall be achieved. HVLP spray guns represent developments in technology for the Business Machines NSPS. Aludec representatives indicated that the facility has never performed surface coating of plastic parts for business machines, but all painting activities use HVLP spray guns. 

HVLP spray guns use lower air pressures and greater volumes than conventional air atomized spray systems and, according to the 2008 CTG, can achieve transfer efficiencies of up to 65 percent with optimal conditions and good operator technique. In comparison, conventional air atomized spray systems have typical transfer efficiencies of 25 to 40 percent. Conventional air atomized spray guns and electrostatic spray guns were identified and considered during BSER development for the Business Machines NSPS. 
The NSPS subpart TTT regulation provides that if an owner or operator can demonstrate to the satisfaction of the Administrator that TE values other than those specified in the NSPS are appropriate, the Administrator will approve their use on a case-by-case basis. Similarly, the Administrator will on a case-by-case basis approve a TE value for an application method not listed in the regulation. This regulatory option provides owners and operators the flexibility to choose the type of application method and TE that matches their desired coating performance and the shape and size of the coated item. 
Coatings, with certain properties, narrow a facility's application technology options. Specifically, highly viscous coatings are difficult to atomize and may prevent the use of conventional air spray guns; further, the shear characteristics of a coating may eliminate the use of airless application. Facilities coating plastic parts for business machines need versatility in application technologies that match the variety of items coated at a job shop. It should be noted that none of the three facilities actively engaged in the surface coating of plastic parts for business machines use HVLP and that a TE of 65 percent may not be achievable. 
A common process modification, robotically mounted guns, is inappropriate for job shops. Robotics allow for consistent positioning and application. The experience of Mack Molding is representative of other job shops. As shown in notes of a meeting with Mack Molding on October 5, 2021, their item diversity and short coating runs were incompatible with use of a robot, given the required robot reset periods.
High-efficiency Coating Spray Guns: As discussed in sections 3.1.1 and 3.1.2 of this memorandum, spray coating application equipment has undergone notable developments since the BSER development for the Business Machines NSPS. The Business Machines NSPS does not contain any standards specifying the type of spray guns that must be used when coatings are spray applied or specifying that high efficiency application methods must be used. However, the VOC content limits established by the NSPS are based on coating solids applied, defined as "the coating solids that adhere to the surface of the plastic business machine part being coated." Therefore, the transfer efficiency of the spray gun has to be included when calculating compliance with the VOC content limits in the Business Machines NSPS. The highest transfer efficiency currently considered in the rule is 0.40 for air-assisted airless spray and electrostatic air spray equipment. As discussed in sections 3.1.1 and 3.1.2 of this memorandum, newer technologies such as HVLP spray guns can achieve transfer efficiencies of up to 65 percent, while improvements in electrostatic and air-assisted airless spray technologies allow them to achieve transfer efficiencies of up to 0.90 and 0.65, respectively. Several surface coating NESHAP specify that high-efficiency spray guns must be used for spray applied coatings (subparts GG, JJ, HHHHHH, XXXXXX) or the compliance demonstration considers the transfer efficiency of the application equipment and the limits are based on high-efficiency spray application (subpart IIII). Using high-efficiency spray application reduces the amount of coating applied compared to conventional spray application and therefore reduces emissions. 
The RBLC search results, state VOC rules, facility contacts, and reviews of permits for business machine plastic parts coating facilities indicate that no facilities were using high-efficiency spray coating application methods to coat plastic parts for business machines. Therefore, for each coating subcategory for which coatings are spray applied, the use of high-efficiency spray guns is not considered a universally available process change or pollution prevention measure.  
Reformulation: Pollution prevention measures that are currently used by the industry and were considered during BSER development include product reformulations for coatings, including waterborne, higher-solids, and powder coatings. A review of regulatory actions promulgated subsequent to the Business Machines NSPS has revealed potential developments in the control of emissions from coating operations. These potential developments are discussed further in the paragraphs below.

The EPA's 2008 CTG for Miscellaneous Metal and Plastic Parts Coatings identified the substitution of higher-solvent coatings with coatings containing little or no solvents as one way to reduce VOC emissions. These coatings include powder coatings, waterborne coatings, higher-solids coatings and ultraviolet (UV)-cured coatings. Powder coatings typically require curing temperatures that exceed the temperature limitations of the plastic parts. However, the 2008 CTG also concluded that many of the low-VOC coatings or coatings with no solvents would not meet the performance requirements of certain plastic coating applications and therefore are not viable options for all plastic parts coating operations. 

As acknowledged in the 1985 BID (p. 3-17), coatings manufacturers are developing powder coatings that can be cured with ultraviolet or infrared radiation. The 2008 CTG also identified this improvement plastic parts coating formulation that was not considered in development of the Business Machines NSPS: the use of UV-cured coatings (either powder or liquid) as an alternative to higher-solvent coatings. 

The use of Ultraviolet/Electron Beam (UV/EB)-cured coatings was not in practice in the coatings industry at the time of BSER development and is considered a development in technology for the Business Machine NSPS. In promulgating the Plastic Parts NESHAP, the EPA determined that that incremental emission reduction of requiring UV/EB-cured coatings would be relatively small and that the additional cost was not warranted. There have been no improvements in UV/EB technology that would justify a change in this conclusion. UV/EB technology is technically feasible and can be adopted as part of a source's compliance strategy. However, among sources that perform surface coating of plastic parts for business machines, the EPA did not identify any sources using UV/EB technology and expects that, similarly to the plastic parts NESHAP, the cost of implementing UV/EB technology would not be feasible for the surface coating of plastic parts for business machines.

We have not identified any other coating reformulation options that were not identified and considered during plastic parts NESHAP development. 

3.1.6Any significant changes in the cost (including cost effectiveness) of applying controls (including controls the EPA considered during the development of the original standards).

Additional detailed information on how the EPA estimated emission reductions and cost effectiveness for the evaluated options, and on the model plant used for that purpose, is provided in the memorandum Estimated Costs/Impacts 40 CFR Part 60 Subpart TTTa.
