Control Techniques Guidelines for Automobile 

and Light-Duty Truck Assembly Coatings 

EPA-453/R-08-006 

September 2008 

Control Techniques Guidelines for Automobile and 

Light-Duty Truck Assembly Coatings 

U.S. Environmental Protection Agency 

Office of Air Quality Planning and Standards 

Sector Policies and Programs Division 

Research Triangle Park, NC 

iii 

TABLE OF CONTENTS 

I. 

II. 

III. 

IV. 

A. 

No 

V. 

A. 

1. 

2. 

B. 

1. 

2. 

C. 

1. 

2. 

3. 

4. 

VI. 

A. 

B. 

VII. 

VIII. 

Introduction 

Background and Overview 2 

Applicability 3 

Process Description and Sources of VOC Emissions 6 

Process Description 7 

1. Surface Preparation 7 

2. Priming Operations 7 

3. Topcoat Operations .8 

4. Final Repair Operations 8 

5. Cleaning Activities 8 

Sources of VOC Emissions 9 

1. Coatings 9 

2. Cleaning Materials 10 

Available Controls and Regulatory Approaches 11 

Available Controls for VOC Emissions from Coatings and Drying 11 

Pollution Prevention Measures 11 

Emission Capture and Add-on Control Systems 12 

Available Controls for VOC Emissions from Cleaning Materials 14 

Product Substitution/Reformulation 14 

Work Practice Procedures 14 

Existing Federal, State, and Local Recommendations or Regulations 14 

The 1977 CTG 15 

The 1980 NSPS 16 

The 2004 NESHAP 17 

Existing State and Local VOC Requirements 18 

Recommended Control Techniques 18 

Coatings 18 

Work Practices for Coating-Related Activities and Cleaning Materials ..22 

Emission Reductions and Cost Effectiveness of Recommended Control Options 23 

References 24 

LIST OF APPENDICES 

Appendix A: Definitions 

Appendix B: 1977 CTG for Surface Coating of Cans, Coils, Paper, Fabrics, Automobiles, 

and Light-Duty Trucks 

Appendix C: Summary of Selected State Regulations for Automobile and Light-Duty Truck 

Assembly Coatings (including Bay Area AQMD) 

I. Introduction 

Clean Air Act (CAA) section 172(c)(1) provides that state implementation plans (SIPs) 

for nonattainment areas must include "reasonably available control measures" (RACM), 

including "reasonably available control technology" (RACT), for sources of emissions. Section 

182(b)(2)(A) provides that for certain nonattainment areas, States must revise their SIPs to 

include RACT for each category of volatile organic compound (VOC) sources covered by a 

control techniques guidelines (CTG) document issued between November 15, 1990 and the 

date of attainment. 

The United States Environmental Protection Agency (EPA) defines RACT as "the 

lowest emission limitation that a particular source is capable of meeting by the application of 

control technology that is reasonably available considering technological and economic 

feasibility." 44 FR 53761 (Sept. 17, 1979). In subsequent Federal Register notices, EPA has 

addressed how States can meet the RACT requirements of the CAA. 

Clean Air Act section 183(e) directs EPA to list for regulation those categories of 

products that account for at least 80 percent of the VOC emissions, on a reactivity-adjusted 

basis, from consumer and commercial products in areas that violate the NAAQS for ozone (i.e., 

ozone nonattainment areas). EPA issued the list on March 23, 1995, and has revised the list 

periodically. See60 FR 15264 (March 23, 1995); see also 71 FR 28320 (May 16, 2006), 70 FR 

69759 (Nov. 17, 2005); 64 FR 13422 (Mar. 18, 1999). Auto and light-duty truck assembly 

coatings are included on the current section 183(e) list. 

This CTG is intended to provide State and local air pollution control authorities 

information that should assist them in determining RACT for VOCs from automobile and lightduty truck assembly coatings. In developing this CTG, EPA, among other things, evaluated the 

sources of VOC emissions from the automobile and light-duty truck assembly coating industry 

and the available control approaches for addressing these emissions, including the costs of such 

approaches. Based on available information and data, EPA provides recommendations for RACT 

for automobile and light-duty truck assembly coating. 

States can use the recommendations in this CTG to inform their own determination as to 

what constitutes R_ACT for VOCs for automobile and light-duty truck assembly coatings in their 

particular nonattainment areas. There are several hazardous air pollutants (HAPs) that are also 

VOCs. The information contained in this document is provided only as guidance. This guidance 

does not change, or substitute for, requirements specified in applicable sections of the CAA or 

EPA's regulations; nor is it a regulation itself. This document does not impose any legally 

binding requirements on any entity. It provides only recommendations for State and local air 

pollution control agencies to consider in determining RACT. State and local pollution control 

agencies are free to implement other technically-sound approaches that are consistent with the 

CAA and EPA's implementing regulations. 

The recommendations contained in this CTG are based on data and information currently 

available to EPA. These general recommendations may not apply to a particular situation based 
upon the circumstances of a specific source. Regardless of whether a State chooses to implement 

the recommendations contained herein through State rules, or to issue State rules that adopt 

different approaches for RACT for VOCs from automobile and light-duty truck assembly 

coatings, States must submit their RACT rules to EPA for review and approval as part of the SIP 

process. EPA will evaluate the rules and determine, through notice and comment rulemaking in 

the SIP approval process, whe.ther the submitted rules meet the RACT requirements of the CAA 

and EPA's regulations. To the extent a State adopts any of the recommendations in this 

guidance into its State RACT rules, interested parties can raise questions and objections about 

the substance of this guidance and the appropriateness of the application of this guidance to a 

particular situation during the development of the State rules and EPA's SIP approval process. 

Clean Air Act section 182(b)(2) requires that a CTG issued between November 15, 1990, 

and the date of attainment include the date by which States subject to section 182(b) must submit 

SIP revisions in response to the CTG. Accordingly, EPA is providing in this CTG a one-year 

period for the required submittal. Pursuant to section 182(b)(2), States required to submit rules 

consistent with section 182(b) must submit their SIP revisions within one year of the date of 

issuance of the final CTG for automobile and light-duty truck assembly coatings. 

II. Background and Overview 

There have been three federal actions that affect automobile and light-duty truck 

assembly coating operations. In May 1977, EPA issued a CTG document (1977 CTG) for 

controlling VOC emissions from surface coating of automobiles and light-duty trucks, In 

December 1980, EPA promulgated the new source performance standards (NSPS) for 

automobile and light-duty truck assembly coating operations (1980 NSPS). 2 In April 2004, 

EPA pr6mulgated the National Emission Standards for Hazardous Air Pollutants: Surface 

Coating of Automobiles and Light-Duty Trucks (2004 NESHAP). 3 

The 1977 CTG, the 1980 NSPS and the 2004 NESHAP provide a thorough discussion of 

the automobile and light-duty truck assembly coating industry, the nature of VOC emissions (or 

in the case of the 2004 NESttAP, organic HAP emissions) from this industry, available control 

technologies for addressing such emissions, the costs of available control options, and other items. 

The 1977 CTG recommends and the 1980 NSPS establishes VOC emissions limits, whereas the 

2004 NESHAP establishes organic HAP emissions limits and does not address non-HAP VOC. 

At least 14 States and one California air pollution control district have specific 

regulations that control VOC emissions from automobile and light-duty truck assembly coating. 

A discussion of the applicability and control options found in the federal actions and State and 

local rules is presented in Section V of this document. 

EPA developed the recommended approaches contained in this document after 

reviewing the 1977 CTG, the 1980 NSPS, the 2004 NESHAP, existing State and local VOC 

emission reduction approaches, and data provided bythe industry in 2008. 

The remainder of this document is divided into six sections. Section III describes the 

scope of sources to which the control recommendations in this CTG could apply. Section IV 
describes the automobile and light-duty truck assembly coating industry, including the types of 

automobile and light-duty trucks, the coating materials and the coating processes, and identifies 

the sources of VOC emissions from those processes. Section V describes the available control 

approaches for addressing VOC emissions from this product category and summarizes Federal, 

State and local approaches •for addressing such emissions. Section V! provides our 

recommendations for RACT for automobile and light-duty truck assembly coating. Section VII 

discusses the cost-effectiveness of the recommended control approaches. Section VIII contains a 

list of references. 

III. App!icabili • 

This section addresses EPA's recommendations as to the scope of entities to which the 

RACT recommendations in this CTG should apply. As explained above, this document is a 

guidance document and provides information for States to consider in determining RACT. 

When State and local pollution control agencies develop RACT rules, they may elect to adopt 

control approaches that differ from those described in this document and/or promulgate 

applicability criteria that differ from those recommended here. 

This CTG provides control recommendations for reducing VOC emissions stemming from 

the use of coatings in automobile and light-duty truck a assembly coating operations. We 

recommend that the control approaches discussed in section VI of this CTG apply to each 

automobile and light-duty truck assembly coating operation at a facility where the total actual 

VOC emissions from all automobile and light-duty truck assembly coating operations, including 

related cleaning activities, at that facility are equal to or exceed 6.8 kg/day (15 lb/day), before 

consideration of controls. We do not recommend these control approaches for facilities that emit 

below this level because of the very small VOC emission reductions that can be achieved. The 

recommended threshold level is equivalent to the evaporation of approximately 2 gallons of 

solvent per day. Such a level is considered to be an incidental level of solvent usage that could 

be expected even in facilities that use very low-VOC content coatings. Furthermore, based on 

the April 2004 ozone nonattainment designations, we estimate that all of the automobile and 

light-duty truck surface coating facilities are located in ozone nonattainment areas and emit 6.8 

kg/day (15 lb/day) or more. Therefore, we expect that our recommendations in this CTG would 

apply to all automobile and light-duty truck surface coating facilities in ozone nonattainment 

areas. 

The automobile and light-duty truck assembly coatings product category under section 

183(e) of the CAA includes the primary coatings b that are applied to (1) new automobile or new 

light-duty truck bodies, or body parts for new automobiles or new light-duty trucks, and (2) other 

parts that are coated along with these bodies or body parts. The category also includes additional 

coatings applied during the vehicle assembly process c. Automobile and light-duty truck assembly 

"Automobile means a motor vehicle designed to carry up to eight passengers, excluding vans, sport utility vehicles, 

and motor vehicles designed primarily to transport light loads of property. Light-duty truck means vans, sport utility 

vehicles, and motor vehicles designed primarily to transport light loads of property with gross vehicle weight rating 

of 8,500 Ibs or less. 

The primary coatings are electrodeposition primer, primer-surfacer, topcoat, and final repair. These coatings are 

defined in Appendix B. 

Coatings applied during the vehicle assembly process include glass bonding primer, adhesives, cavity wax, sealer, 
coatings most commonly are applied at automobile or light-duty truck assembly plants. 

ttowever, this 183(e) category also includes coatings used in facilities that perform these coating 

operations on a contractual basis. This category does not include coatings used at plastic or 

composites molding facilities as described in the Surface Coating of Automobiles and LightDuty Trucks NESHAP (40 CFR part 63, subpart IIII). Please see section IV of this CTG for 

further description of the auto and light-duty truck assembly coatings category under section 

183(e) of the CAA. 

In addition to the coating applications described above, automobile and light-duty truck 

assembly coating facilities may have separate coating lines on which coatings are applied to 

other parts intended for use in new automobiles or new light-duty trucks (e.g., application of 

spray primer, color and clear coat to fascia or bumpers) or to aftermarket repair or replacement 

parts for automobiles or light-duty trucks. The separate coating of these other parts and 

aftermarket or replacement parts is included in the Miscellaneous Metal Products and Plastic 

Parts Coatings categories under section 183(e) and covered in the CTG for those categories. 

However, States may want to evaluate, given the facts and circumstances of the automobile and 

light-duty truck assembly coating facilities in their states, whether it is appropriate to give these 

facilities the option of having their separate coating of other parts and aftermarket repair or 

replacement parts, as described above, covered under the State miscellaneous metal and plastic 

parts coatings RACT rule or the State automobile and light-duty truck assembly coating RACT 

rule. 

Furthermore, we recommend that states consider structuring their RACT rules to provide 

thcilities that coat bodies and/or body parts for new heavier vehicles d with the option of meeting 

either the state RACT requirements for the automobile and light-duty truck coating category or 

the state RACT requirements for the miscellaneous metal products or plastic parts coatings 

categories. Heavier vehicle coatings are included in the Miscellaneous Metal Products and 

Plastic Parts Coatings categories under section 183(e) and are therefore covered in the CTG for 

Miscellaneous Metal and Plastic Parts Coatings. We note, however, that some automobile and 

light-duty truck assembly coating facilities also coat new heavier vehicle bodies or body parts for 

new heavier vehicles. The new heavier vehicle bodies or body parts for new heavier vehicles 

may be coated using the same equipment and materials that are used to coat new automobile and 

light-duty truck bodies or body parts for new automobiles and light-duty trucks. The permit 

requirements for the heavier vehicle portion of these combined use paint shops are often 

structured in the same way as permit requirements for automobile and light-duty truck paint 

shops. Also, some facilities that coat only new heavier vehicle bodies or body parts for new 

heavier vehicles have paint shops that are designed and operated in the same manner as paint 

shops that are used to coat new automobile and light-duty truck bodies and body parts for new 

automobiles and light-duty trucks. The permit requirements for these heavier vehicle paint shops 

are often structured in the same way as permit requirements for automobile and light-duty truck 

paint shops. 

deadener, gasket/gasket sealing material, underbody coating, trunk interior coating, bedliner, weatherstrip adhesive, 

and lubricating waxes/compounds. These coatings are defined in Appendix B. 

Heavier vehicles includes all vehicles that meet the definition.of the term "other motor vehicles", as defined at 40 

CFR § 63.3176 (the NESHAP for Surface Coating of Automobiles and Light-Duty Trucks). 
In light of the above, providing facilities that coat bodies and/or body parts for new 

heavier vehicles with the option of meeting the state RACT requirements for the automobile and 

light-duty .truck coating category in lieu of the requirements for Miscellaneous Metal Products or 

Plastic Parts categories will provide for the most consistency with existing permit requirements 

and simplify compliance demonstration requirements for these facilities. Furthermore, in light of 

the stringency of our recommended control measures in this CTG, we believe that facilities that 

choose this alternative will achieve at least equivalent, if not greater, control of VOC emissions. 

For the reasons stated above, we recommend that state RACT rules provide facilities that coat 

bodies and/or body parts for new heavier vehicles the option of meeting either the state RACT 

requirements for miscellaneous metals and plastic parts coatings or the state RACT requirements 

for auto and light-duty truck coatings. 

Like automobile and light-duty truck assembly coating facilities, facilities that coat 

bodies and/or body parts for new heavier vehicles may have separate coating lines on which 

coatings are applied to other parts intended for use in new heavier vehicles, or to aftermarket 

repair or replacement parts for heavier vehicles. The separate coating of these other parts and 

aftermarket or replacement parts is included in the Miscellaneous Metal Products and Plastic 

Parts Coatings categories under section 183(e) and covered in the CTG for that category. As 

mentioned above, we recommend that State RACT rules provide facilities that coat bodies and/or 

body parts for new heavier vehicles with the option of meeting either the state RACT 

requirements for automobile and light-duty truck coatings or the state RACT requirements for 

miscellaneous metal products or plastic parts coatings. States that choose to provide this option 

may also want to evaluate, given the facts and circumstances of the heavier vehicle coating 

facilities at issue in their states, whether it is appropriate to give these facilities the option of 

having their separate coating of other parts and aftermarket repair or replace, ment parts, as 

described above, covered under the State miscellaneous metal and plastic parts coatings RACT 

rule or the State automobile and light-duty truck assembly coating RACT rule. 

For purposes of determining whether a facility meets our recommended applicability 

threshold, aggregate emissions, before consideration of control, from all automobile and lightduty truck assembly coating operations (including related cleaning activities) at a given facility 

are included. 

In developing RACT rules, State and local agencies should consider carefully the facts 

and circumstances of the affected sources in their States. As noted above, States can adopt the 

above recommended 6.8 kg/day (15 lb/day) actual VOC emissions or an equivalent applicability 

threshold, or they can develop other applicability criteria that they determine are appropriate 

considering the facts and circumstances of the sources in their particular nonattainment areas. 

EPA will review the State RACT rules in the context of the SIP revision process. 

There are currently 52 automobile and light-duty truck assembly facilities that engage in 

surface coating operations in the United States. The highest concentration of these facilities are 

in Michigan, Illinois, Indiana, and Ohio. 

For the development of this CTG, we considered VOC emissions data from information 

gathered during the development of the 2004 NESHAP. We also considered VOC emissions data 
submitted in 2008 by the Alliance of Automobile Manufacturers member companies and nonmember companies. 

The 2004 NESHAP survey collected information for 61 facilities in operation in 1996. 

Although information regarding HAP emissions was the main focus of the NESHAP survey, 

information regarding VOC emissions was also submitted. 

The Alliance for Automobile Manufacturers member companies and non-member 

companies submitted VOC emissions data for calendar years 2006 and 2007. Emissions 

information from surface coating operations during automobile and light-duty truck. 

manufacturing was provided on a daily minimum, daily maximum, and daily and monthly 

average basis. Information was provided for 52 facilities located in the United States. 

The 2002 National Emissions Inventory (NEI) contains information for 48 of these 52 

facilities. (The other four facilities were not yet operating in 2002.) These 48 facilities reported 

actual VOC emissions totaling approximately 27,500 tons in 2002. 

IV. Process Description and Sources of VOC Emissions 

The auto and light-duty .truck assembly coatings product category under section 183(e) 

of the CAA includes the coatings that are applied to new automobile or new light-duty truck 

bodies, or body parts for new automobiles or new light-duty trucks. The large majority of these 

coatings are specifically formulated, marketed and sold for this end use and are applied at 

automobile or light-duty truck assembly plants. However, this 183(e) category also includes 

coatings used in facilities that perform these coating operations on a contractual basis. This 

category does not include coatings used at plastic or composites molding facilities as described 

in the Surface Coating of Automobiles and Light-Duty Trucks NESHAP (40 CFR part 63, 

subpart IIII). 

Automobile and light-duty truck coatings enhance a vehicle's durability and appearance. 

Some of the coating system characteristics that automobile and light-duty truck manufacturers 

test for include adhesion, water resistance, humidity resistance, salt spray resistance, color, gloss, 

acid etch resistance, and stone chip resistance. The primary coatings used are electrodeposition 

primer, primer-surfacer (including anti-chip coatings), topcoat (basecoat and clearcoat) and final 

repair. Glass bonding primer, adhesives, cavity wax, sealer, deadener, gasket/gasket sealing 

material, underbody coating, trunk interior coating, bedliner, weatherstrip adhesive, and 

lubricating waxes/compounds also are used at automobile or light-duty assembly coating 

facilities. These coatings are included as "automobile and light-duty truck" materials in the 

automobile and light-duty truck assembly coatings product category and are addressed in this. 

CTG. 

Glass bonding primer, adhesives, cavity wax, sealer, deadener, gasket/gasket sealing 

material, underbody coating, trunk interior coating, bedliner, weatherstrip adhesive, and 

lubricating waxes/compounds also are used in the production of vehicles other than automobiles 

or light-duty trucks, and may be used in activities related to the production of new automobiles 

or new light-duty trucks or aftermarket parts for automobiles and light-duty trucks at facilities 
that are not automobile or light-duty truck assembly coatings facilities. These materials are 

included as "motor vehicle" materials in the miscellaneous metal products and plastic parts 

coatings categories or the miscellaneous industrial adhesives category, and are addressed in the 

CTGs for those categories. The recommended limits for the "motor vehicle" materials in the 

CTGs for those categories are the same as the recommended limits for "automobile and lightduty truck" materials in this CTG. Definitions and VOC control recommendations for the 

following types of materials are included in the miscellaneous metal and plastic coatings CTG: 

motor vehicle cavity wax, motor vehicle sealer, motor vehicle deadener, motor vehicle trunk 

interior coating, motor vehicle bedliner, motor vehicle gasket/gasket sealing material, motor 

vehicle underbody coating, and motor vehicle lubricating wax/compound. Definitions and VOC 

control recommendations for the following types of materials are included in the miscellaneous 

industrial adhesives CTG: motor vehicle glass bonding primer, motor vehicle adhesive, and 

motor vehicle weatherstrip adhesive. 

Aerosol coatings are not included in the automobile and light-duty truck assembly 

coating category. Aerosol coatings are a separate category under section 183(e) and are 

addressed by the national VOC rule for aerosol coatings. 

A. Process Description 

The coating process for automobiles and light-duty trucks consists of the following 

operations: (1) surface preparation, (2) priming operations, (3) topcoat operations, (4) final 

repair operations, and (5) cleaning activities. In addition, cleaning activities are performed in 

support of the surface coating operation. These operations and activities are further described. 

below. 

1. Surface Preparation 

Surface preparation occurs before coatings are applied. During this preparation stage, the 

body of an automobile or light-duty truck is assembled, anticorrosion operations are performed, 

and any plastic parts to be finished with the body are installed. 

2. Priming Operations 

After the body has been assembled, anticorrosion operations have been performed, and 

plastic parts to be finished with the body are installed, priming operations begin. The purpose of 

the priming operations is to further prepare the body for finishing by applying various layers of 

coatings designed to protect the metal surface from corrosion and assure good adhesion of 

subsequent coatings. 

First, an electrodeposited primer (EDP) coating is applied to the body using a method in 

which a negatively charged automobile or light-duty truck body is immersed in a positively 

charged bath of waterborne electrodeposition primer. The coating particles (resin and pigment) 

migrate toward the body and are deposited onto the body surface, creating a strong bond between 

the coating and the body to provide a durable coating. Once the coating application deposition is 

completed, the body. is rinsed in a succession of individual spray and/or immersion rinse stations 
and then dried with an automatic air blow-off. Following the rinsing stage (including the 

automatic air blow-off), the deposited coating is cured in an electrodeposition curing oven. 

After curing, the body is further water-proofed by sealing spot-welded joints of the body. 

After sealing, the body proceeds to the anti-chip booth where anti-chip coatings are applied to 

protect the vulnerable areas of the body. 

Next, a primer-surfacer coating is applied. The purpose of the primer-surfacer coating is to 

provide "filling" or hide minor imperfections in the body, provide additional protection to the 

vehicle body, and bolster the appearance of the topcoats. Primer-surfacer coatings are applied by 

spray application in a water-wash spray booth. Following application of the primer-surfacer, the 

body is baked to cure the film, minimize dirt pickup, and reduce processing time. 

3. Topcoat Operations 

The next step of the coating process is the spray application of the topcoat, which usually 

consists of a basecoat (color) and a clearcoat. The purpose of the clearcoat is to add luster and 

durability to the vehicle finish and protect the total coating system against solvents, chemical 

agents, water, weather, and other environmental effects. 

After the topcoat (i.e., a basecoat and a clearcoat) is applied, the automobile or light-duty 

truck body or body parts proceed to a flash-off area, where a certain level of solvent evaporation 

occurs. This step is designed to prevent bubble formation during curing in the bake oven. After 

flash-off, the automobile and light-duty truck bodies or body parts are then dried/cured in bake 

ovens. 

4. Final Repair Operations 

Final repair means the operations performed and coating(s) applied to completelyassembled motor vehicles or to parts that are not yet on a completely assembled motor vehicle to 

correct damage or imperfections in the coating. The curing of the coatings applied in these 

operations is accomplished at a lower temperature than that used for curing primer-surfacer and 

topcoat. This lower temperature cure avoids the need to send parts that are not yet on a 

completely assembled vehicle through the same type of curing process used for primer-surfacer 

and topcoat and is necessary to protect heat sensitive components on completely assembled 

motor vehicles. 

5. Cleaning Activities 

Cleaning materials are used for several purposes, including the removal of coating 

residue or other unwanted materials from equipment related to the coating operations such as 

spray guns, transfer lines (e.g., tubing or piping), tanks, and the interior of spray booths. These 

cleaning materials are typically mixtures of organic solvents. 

Work practices are widely used throughout the automobile and light-duty truck 

manufacturing industry to reduce VOC emissions from cleaning operations. These measures 
include covering mixing tanks and storing solvents and solvent soaked rags and wipes in closed 

containers. Another method is the use of low-VOC content or low vapor pressure cleaning 

materials. However, there is insufficient information available to correlate VOC content or 

vapor pressure to specific cleaning steps. 

B. Sources of VOC Emissions 

VOC emissions depend on VOC content, transfer efficiency, and the presence and extent of 

VOC control equipment. To lower VOC content, liquid coatings can be reformulated. VOC 

contents and emission rates for solvent-borne and waterborne materials also have overlapping 

ranges. 

The VOC emissions from automobile and light-duty truck assembly coating operations are 

primarily a result of evaporation of the VOC contained in the coatings and cleaning materials used 

in these operations. • The primary VOC emissions from automobile .and light-duty truck assembly 

coatings occur during coating application/flash-off and drying/curing of the coatings. The 

remaining emissions occur mainly from mixing and/or thinning. The VOC emissions from mixing 

and thinning of coatings occur from displacement of VOC-laden air in containers used to mix 

coatings containing solvents (thinners) prior to coating application. The displacement of VOCladen air can also occur during filling of containers and can be caused by changes in temperature, 

changes in barometric pressure, or agitation during mixing. Another source of VOC emissions 

from automobile and light-duty truck assembly coating operations is cleaning materials. The 

VOC are emitted when solvents evaporate from the cleaning materials during use. In most cases, 

VOC emissions from surface preparation, storage, handling, and waste/wastewater operations are 

relatively small. The following discussion describes these primary emission sources (coatings 

and cleaning materials). 

1. Coatings 

The VOC emissions from coating application occur when solvent evaporates from the 

coating as it is being applied to the vehicle part or. body. The transfer efficiency (the ratio of the 

amount of coating solids deposited onto the surface of the object to the total amount of coating 

solids sprayed while applying the coating to the object) of a coating application method affects 

the amount of VOC emitted during coating application. A coating application method that is more 

efficient in transferring coatings to the substrate will reduce the volume of coatings (and therefore 

solvents) needed per given amount of production, thus reducing VOC emissions.. 

Until the 1970's, the majority of coatings used in the automobile and light-duty truck 

manufacturing industry were conventional solvent-borne coatings, which have high VOC 

In a previous notice, EPA stated that the cleaning operations associated with certain specified section 183(e) 

consumer and commercial product categories, including the automobile and light duty truck assembly coatings 

category, would not be covered by EPA's 2006 CTG for industrial cleaning solvents (71 FR 44522, 44540, August 

4, 2006). In the notice, EPA expressed its intention to address cleaning operations associated with these categories in 

the CTGs for these specified categories if the Agency determines that a CTG is appropriate for the respective 

categories. Accordingly, this CTG addresses VOC emissions from cleaning operations associated with the 

automobile and light-duty truck assembly coatings category. 
content. Due to a combination of regulation at the State and federal level, technology 

development and competitive factors, the industry has steadily moved to lower VOC content 

coatings. These alternative coatings include powder coatings, waterborne coatings, and .higher 

solids solvent-borne coatings. The utilization of these alternative coatings in conjunction with 

efficient spray application equipment, such as electrostatic spray, is the primary method that is 

currently being used at auto and light-duty truck assembly coating operations to reduce VOC 

emissions from the coatings. In addition, many facilities control the exhaust from their bake 

ovens. Some facilities have also employed partial spray booth controls by venting spray booth 

emissions, principally from automated spray zones, through an add-on control device such as an 

oxidizer or hybrid (concentrator followed by an oxidizer) control system. 

Powder anti-chip and primer-surfacer coatings are used at some automobile and lightduty truck assembly plants. Powder coating produces minimal amounts of VOC emissions. 

Powder coating is applied via powder delivery systems, which in most cases is an electrostatic 

spray. Because powder coatings are applied as dried particles, no VOC are released during the 

application operation. Depending on the powder formulation, some volatile emissions may 

occur when the powder is heated during the curing step. In any event, any volatile emissions 

from the heating of powder coatings would generally be much less than the volatile emissions 

from the heating of liquid coatings during the curing operations. Powder coating applications are 

best suited for long production runs of consistently sized parts without color changes. Powder 

anti-chip and primer-surfacer coatings are used at some automobile and light-duty truck 

assembly plants. 

Waterborne coatings produce less VOC emissions than conventional solvent-borne 

coatings primarily because a large portion of the organic solvent carrier (VOC) is replaced with 

water. Waterborne electrodeposition primers are used at almost every automobile and light-duty 

truck assembly plant. Waterborne primer-surfacer and waterborne basecoat are used at some 

automobile and light-duty truck assembly plants. Waterborne primer-surfacer and waterborne 

basecoat are applied by a combination of manual and automatic, and electrostatic and nonelectrostatic spray techniques. 

Higher solids solvent-borne coatings contain more solids than "conventional" (pre-1980) 

solvent-borne coatings. These coatings contain less orgal•ic solvent (VOC) per unit volume of 

solids than conventional solvent-borne coatings. Thus, a lesser amount of VOC emissions are 

released during coating preparation, application, and curing to deliver a given amount of coating 

solids. Higher solids primer-surfacer and basecoat are used at some automobile and light-duty 

truck assembly plants. Higher solids clearcoat is used at every automobile and light-duty truck 

assembly plant. Higher solids primer-surfacer and basecoat are applied by a combination of 

manual and automatic, and electrostatic and non-electrostatic spray techniques. 

Additional VOC .emissions occur in the flash-off area after coatings are applied and in 

baking ovens where drying and curing occurs. 

2. Cleaning Materials 

Cleaning materials are another source of VOC emitted by automobile and light duty 
truck surface coating operations. The VOC are emitted when solvents evaporate from the 

cleaning materials during use. 

Cleaning materials with low-VOC composite vapor pressure and/or low-VOC content 

generate less VOC .emissions than materials with higher VOC vapor pressure and/or content. 

The VOC composite vapor pressure of a cleaning material is a weighted average of the vapor 

pressures of the VOC components of that cleaning material. The vapor pressure of each VOC 

component is weighted by the mole fraction of that VOC component in the whole cleaning 

material, including non-VOC components such as water or exempt compounds, Water and 

exempt compounds thereby reduce the VOC composite vapor pressure of cleaning materials in 

which they are present. Although use of lower vapor pressure cleaning materials may reduce 

VOC emissions, insufficient information is available to correlate cleaning material vapor 

pressure to specific cleaning steps in the automobile and light-duty truck surface coating 

industry. Similarly, cleaning materials with low VOC content would generate less VOC 

emissions than materials with high VOC content; however, insufficient information is available 

to correlate cleaning material VOC content to specific cleaning steps in this industry. 

V. Available Controls and Regulatory. Approaches 

As previously mentioned, there are two main sources of VOC emissions from automobile 

and light-duty truck assembly coating operations: (1) evaporation of VOC from the coatings and 

drying; and (2) evaporation of VOC from the cleaning materials. This section summarizes the 

available control options for reducing these VOC emissions and existing federal, State, and local 

VOC recommendations or requirements that address these emissions. 

A. Available Controls for VOC Emissions from Coatings and Drying 

There are two general emission control techniques for reducing VOC emissions from 

automobile and light-duty truck assembly coatings: pollution prevention measures, and emission 

capture and add-on control systems. Pollution prevention is the most prevalent control technique 

being used by the automobile and light-duty truck manufacturing industry. Add-on control 

systems are also used in this industry. Provided below is a summary of these control techniques. 

1. Pollution Prevention Measures 

Pollution prevention measures applicable to the automobile and light-duty truck 

manufacturing industry, including product substitution/reformulation, work practice procedures, 

and equipment substitution, may be used to decrease VOC emissions from coating application 

operations: Lower VOC content coatings, such as powder coatings, higher solids solvent-borne 

coatings and waterborne coatings, may be used to reduce VOC emissions by reducing or 

eliminating the organic solvent present in the coating. Work practice procedures may also result 

in VOC emission reductions during the coating process by reducing coating waste. The use of 

efficient coating application equipment reduces VOC emission by increasing the coating transfer 

Exempt compounds are those classified by EPA as having negligible photochemical reactivity as listed in 40 CFR 

1.100 (s). Exempt compounds are not considered to be VOC. 

11 
efficiency (i.e., the percentage of coating solids used that is deposited onto the substrate). 

Product substitution

One pollution prevention measure is to replace higher-solvent coatings with coatings 

containing little or no solvents. As previously discussed, these coatings include waterborne 

coatings, higher solids solvent-borne coatings, and electrodeposition coatings. The use of higher 

solids and waterborne coatings has increased since the 1970's. 

Work Practices 

Work practice procedures are physical actions intended to affect emission reductions. 

Because work practice procedures are specifically tailored to an industry, they may vary from a 

few manual operations to a complex program. 

Coating waste is generated during coating material preparation, coating application, and 

equipment cleaning. If coating waste is reduced, overall VOC emissions from coating operations 

will be reduced because less VOC coating material will be needed for production. Coating waste 

may be reduced through work practices by effectively controlling material preparation and using 

proper equipment maintenance procedures. 

Equipment Substitution 

The use of efficient coating application equipment reduces VOC emission by increasing 

the coating transfer efficiency (i.e., the percentage of coating solids used that is deposited onto 

the substrate). Since the 1970's the spray equipment used to apply automobile and light-duty 

truck assembly coatings has become increasingly automated. A significant amount of coating is 

applied by reciprocators or robots. At the same time there has also been an increase in the 

amount of paint applied electrostatically. 

2. Emission Capture and Add-on Control Systems 

In addition to pollution prevention measures, VOC emissions from automobile and lightduty truck assembly coating application operations can be reduced by the use of capture systems, 

in conjunction with add-on control systems that either destroy or recover the VOC in the exhaust 

streams. As stated previously, many facilities control the exhaust from their bake ovens. Some 

facilities have also employed partial spray booth controls by venting spray booth emissions, 

principally from automated spray zones, through an add-on control device such as an oxidizer or 

hybrid (concentrator followed by an oxidizer) control system. Spray booths typically exhaust a 

high volume of air with a low concentration of VOC which can result in a high cost of control. 

Capture Systems 

Capture systems collect solvent-laden air from process vents (e.g., spray booth, flash-off 

or bake oven vents) and direct the captured air to a control device. The majority of VOC 

12 
emissions from automobile and light-duty truck assembly coating occur in the spray booth. 

These emissions can be ducted from the spray booth directly to the control device. Similarly, 

flash-off area or bake oven exhaust can be ducted directly to the control device. Spray booths 

and bake ovens are the principal elements of the capture system. 

The design of the capture system can greatly contribute to the overall VOC control 

efficiency. An efficient capture system maximizes the capture of emissions and minimizes the 

capture of dilution air. Spray booth and bake oven design and air management can reduce the 

volume of exhaust air and increase the VOC concentration of the exhaust air which can reduce 

the cost of control. Facilities may combine several captured VOC-laden streams and duct them 

to a single control device. 

Add-on Control Systems 

Add-on controls reduce the amount of VOC emissions by either destruction or recovery 

with or without recycling of VOC emission in the exhaust streams. Two categories of add-on 

control devices are typically used by the automobile and light-duty truck assembly coatings 

operations: combustion (thermal or catalytic oxidation) and recovery (adsorption). While many 

types of control devices can be used to reduce VOC emissions, the following summary covers 

those control devices known to be used with automobile and light-duty truck surface coating 

operations: oxidation and hybrid systems (concentrator followed by an oxidizer). 

Oxidation destroys VOC emissions in an exhaust stream by exposing the stream to an 

oxidizing atmosphere at high temperatures. Oxidizers are typically used in the automobile and 

light-duty truck surface coating industry to control bake oven exhaust emissions. Oxidizers may 

be of thermal or catalytic design and.combust VOC-containing exhaust streams. Catalytic 

oxidizers are similar to thermal oxidizers but employ a catalyst to aid in the oxidation reaction. 

As a result, catalytic oxidizers operate at lower combustion temperatures relative to that required 

in thermal oxidizers. Both types of oxidizers generally utilize either regenerative or recuperative 

techniques to preheat inlet gas in order to decrease energy costs associated with high oxidation 

temperatures. They may also use primary or secondary heat recovery to reduce energy 

consumption. In general, oxidizers may achieve destruction efficiencies of greater than 95 

percent as applied to coating application operations with high and constant concentrations of 

VOC. 

Hybrid systems consist of a concentrator followed by an oxidizer. Hybrid systems are 

used in the automobile and light-duty truck surface coating industry to control spray booth 

exhaust emissions, most often exhaust from automated zones of the spray booth. The 

concentrator is typically a carbon or zeolite rotor..The concentrator reduces the volume and 

increases the VOC concentration of the inlet stream to the oxidizer. 

Spray booth exhaust contains overspray particles. The majority of these particles are 

removed by the spray booth water wash. Additional pretreatment of the spray booth exhaust is 

required before it passes through a concentrator. This additional pretreatment may be done with 

dry filters or a dry electrostatic precipitator. 

13 
In addition, there are other control technologies known to reduce VOC emissions, but 

they are not currently being used in the automobile and light-duty truck surface coating industry. 

These altemative control technologies include condensation, biofiltration, and UV oxidation.. 

B. Available Controls for VOC Emissions from Cleaning Materials 

Pollution prevention measures, such as work practices, are the most common emission control 

technique for reducing VOC emissions from cleaning materials. Work practice procedures 

reduce VOC emission during cleaning operations by reducing the amount of VOC that can 

evaporate due to exposure to air. Product substitution/reformulation is another type of pollution 

prevention measures. 

No add-on control technologies are being used specifically for reducing VOC emissions 

from cleaning operations associated with automobile and light-duty truck assembly coating. 

However, if cleaning operations are performed within a capture system that is ducted to an addon control system, the VOC emissions from the cleaning operations would be reduced by the 

add-on control. 

1. Product Substitution/Reformulation 

Reducing the composite VOC vapor pressure or VOC content of the cleaning material 

used, either by substitution or reformulation, is one pollution prevention measure that is used to 

reduce VOC emissions from cleaning operations. However, there is insufficient information 

available to correlate VOC content or vapor pressure to specific cleaning steps. 

2. Work Practice Procedures 

Work practice procedures are commonly used in the automobile and light-duty truck 

manufacturing industry to reduce VOC emissions from cleaning operations. These procedures 

include the following: 

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. 

C, Existing Federal, State, and Local Recommendations or Regulations 

The following discussion is a summary of three EPA actions, as well as State and local 

regulations, which address VOC emissions from automobile and light-duty truck assembly 

coating processes. 

Three previous EPA actions affected automobile and light-duty truck assembly coating 

operations: 

14 
CTG for Surface Coating of Cans, Coils, Paper• Fabrics, Automobiles, and Light-Duty 

Trucks (1977). 

New Source Performance Standard for Automobile and Light- Duty Truck Surface 

Coating Operations, 40 CFR Part 60, subpart MM (1980). 

National Emission Standards for Hazardous Air Pollutants for Surface Coating of 

Automobile and Light-Duty Trucks, 40 CFR 63, subpart IIII (2004). 

1. The 1977 CTG 

In 1977, EPA issued a CTG document entitled "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) The 1977 CTG and subsequent 

implementation guidance provided RACT recommendations for controlling VOC emissions 

from automobile and light-duty truck assembly surface coating operations. These 

recommendations are summarized in Table 1. 

The subsequent implementation guidance included the publication in 1988 of a 

document titled "Protocol for Determining the Daily Volatile Organic Compound Emission Rate 

of Automobile and Light-Duty Truck Topcoat Operations" (EPA-450/3-88-018). This 

document is commonly referred to as the Automobile Topcoat Protocol. The Automobile 

Topcoat Protocol provides procedures and calculations for determining the daily VOC emission 

rate of automobile and light-duty truck topcoat operations. These procedures and calculations 

can also be applied to primer-surfacer operations. Most automobile and light-duty truck 

facilities use the 1988 protocol for both their topcoat and primer-surfacer operations. 

Table 1. 1977 CTG Recommended VOC Emission Limits for Automobile and Light-Duty 

Truck Surface Coatings 

Electrodeposition 

primer operation 

Primer-surfacer 

(guidecoat) operation 

Topcoat operation 

Final repair operation 

0.14 kg VOC/liter (1.2 lbs/gal) of coating, excluding water and 

exempt compounds g, or 

0.17 kg VOC/liter (1.4 lb VOC/gallon) of coating solids deposited 

1.8 kg VOC/liter (15.1 lb VOC/gallon) of coating solids deposited on 

a daily average basis as determined by following the procedures in the 

Automobile Topcoat Protocol. 

1.8 kg VOC/liter (15.1 lb VOC/gallon) of coating solids deposited on 

a daily average basis as determined by following the procedures in the 

Automobile Topcoat Protocol. 

0.58 kg VOC/liter (4.8 lbs/gal) of coating, excluding water and 

exempt compounds 

Exempt compounds are those classified by EPA as having negligible photochemical reactivity as listed in 40 CFR 

1.100 (s). Exempt compounds are not considered to be VOC. 

15 
2. The 1980 NSPS 

In 1980, EPA promulgated an NSPS for surface coating of automobile and light-duty 

trucks (40 CFR part 60 subpart MM). The NSPS established the emission limits calculated on a 

monthly basis for each primecoat operation, guidecoat. (primer-surfacer) operation, and topcoat 

operation located in an automobile or light-duty truck assembly plant constructed, reconstructed, 

or modified after October 5, 1979 (Table 2). The NSPS does not apply to plastic body 

component coating operations or to all-plastic automobile or light-duty truck bodies coated on 

separate coating lines. The VOC emission limit for primecoat operations depends on the solids 

turnover ratio (Rt). The solids turnover ratio is the ratio of total volume of coating solids added 

to the EDP system in a calendar month to the total volumetric design capacity of the EDP 

system. The NSPS limits and the 1977 CTG recommendations for primer-surfacer and topcoat 

cannot be directly compared because of differences in the compliance period (monthly for the 

NSPS limits and daily for the CTG recommendations) and how transfer efficiency is considered 

(table values for the NSPS limits and actual transfer efficiency testing for the CTG 

recommendations). 

Table 2. 1980 NSPS VOC Emission Limits for Automobile and Light-duty Truck 

Surface Coatings 

Primecoat Operations 

(Non-EDP) 

Primecoat Operations 

(EDP) 

Guidecoat Operations 

(including the 

guidecoat application, 

flash-off area, and 

oven) 

Topcoat Operations 

(including topcoat 

application, flash-off 

area, and oven) 

0.17 kg VOC/liter (1.42 Ib/gal) coating solids applied 

When solids turnover 

ratio (Rr)>0.16: 

0.17 kg VOC/liter 

(1.42 lb/gal) coating 

solids applied 

When 

0.040<Rr<0.160: 

0.17x350°•'°-ur kg 

VOC/liter 

(0.17x350° 16°nr x 

8.34 lb/gal) 

coating solids 

applied 

When Rr<0:040: 

No VOC emission 

limit 

1.40 kg VOC/liter (11.7 lb/gal) coating solids applied 

1.47 kg VOC/liter (12.3 lb/gal) coating solids applied 

16 
3. The 2004 NESHAP 

In 2004, EPA promulgated the National Emissions Standards for Hazardous Air 

Pollutants: Surface Coating of Automobile and Light-Duty Trucks, 40 CFR, part 63, subpart IIII. 

The areas covered by the NESHAP include all the equipment used to apply coating to new 

automobile or light-duty truck bodies or body parts and to dry or cure the coatings after 

application; all storage containers and mixing vessels in which vehicle body coatings, thinners, 

and cleaning materials are stored and mixed; all manual and automated equipment and containers 

used for conveying vehicle body coatings, thinners, and cleaning materials; and all storage 

containers and all manual and automated equipment and containers used to convey waste 

materials generated by an automobile and light-duty truck assembly coating operation. 

The 2004 NESHAP for automobile and light-duty truck assembly coating imposed 

organic HAP emission limitations calculated on a monthly basis for existing sources. More 

stringent limits .apply to new sources (i.e., sources that commenced construction after December 

24, 2002). The NESHAP also sets emission limits for coatings not included in the CTG or 

NSPS, including glass bonding primer, glass bonding adhesive, and some coatings and thinners. 

The limits for automobile and light-duty truck assembly coating for existing and new sources are 

summarized in Table 3 below. 

Table 3. 2004 NESHAP HAP Emission Limits for Automobile and Light-Duty 

Truck Surface Coatings 

Combined primer-surfacer, topcoat, final 

repair, glass bonding primer, and glass 

bonding adhesive operation plus all 

coatings and thinners, except for deadener 

materials and for adhesive and sealer 

materials that are not components of glass 

bonding systems, used in coating 

operations added to the affected source 

Combined electrodeposition primer, 

primer-surfacer, topcoat, final repair, glass 

bonding primer, and glass bonding 

adhesive operation plus all coatings and 

thinners, except for deadener materials and 

for adhesive and sealer materials that are 

not components of glass bonding systems, 

used in coating operations added to the 

affected source 

0.060 kg organic HAP/liter of coating 

solids deposited (0.50 lb/gal) for new or 

reconstructed affected sources 

0.132 kg organic HAP/liter of coating 

solids deposited (1.10 lb/gal) for existing 

affected sources 

0.036 kg ofganic HAP/liter of coating 

solids deposited (0.30 lb/gal) for new or 

reconstructed affected sources 

0.072 kg organic HAP/liter of coating 

solids deposited (0..60 lb/gal) forexisting 

affected sources 

The 2004 NESHAP for automobile and light-duty truck assembly coating also 

specified work practices to minimize organic HAP emissions from the storage, mixing, and 

conveying of coatings, thinners, cleaning materials, and from handling waste materials 

17 
generated by the coating operation. 

4. Existing State and Local VOC Requirements 

In addition to the EPA actions described above, at least 14 States and one California 

air pollution control district have regulations that control VOC emissions from automobile 

and light-duty truck assembly coating. 

Most of the state rules reviewed had limits that are consistent with the 1977 CTG 

recommended limits. The state rules are summarized in Appendix C. 

VI. Recommended Control Techniques 

This CTG recommends the following VOC reduction measures: VOC emission limits for 

coating operations; work practices for storage and handling of coatings, thinners, and coating 

waste materials; and work practices for the handling and use of.cleaning materials. 

During the development of the 2004 NESHAP, EPA identified 61 automobile and lightduty truck assembly facilities operating in 1999. In 2008, the Alliance of Automobile 

Manufacturers, an industry trade association representing the majority of these facilities, 

provided EPA information from its member companies. Non-member companies also submitted 

information to EPA. EPA reviewed and evaluated this information in conjunction with 

developing this CTG. In total, EPA received information for 52 facilities. The information 

included VOC emission rates for EDP, primer-surfacer, and topcoat operations on a daily and 

monthly average for the calendar years 2006 and 2007. Most facilities also provided data 

showing maximum and minimum daily values, as well. The VOC emission limits recommended 

in this CTG are based on 2006 and 2007 data from currently operating automobile and light-duty 

truck assembly coating operations, and the work practices recommendations mirror those found 

in the NESHAP. 

For cleaning materials, we are recommending work practices to reduce VOC emissions. 

We do not have information available to correlate VOC content or vapor pressure to specific 

cleaning steps. Therefore, we are not recommending VOC content or VOC composite vapor 

pressure limits for cleaning materials. 

The following discussion summarizes our specific recommendations for coating 

operations and cleaning materials used in automobile and light-duty truck assembly coating 

operations. 

A. Coatings 

The following VOC emission limits are recommended to reduce VOC emissions 

from the coatings during the coating operations (Table 5). The categories reflect the current 

processes that are used at automobile and light-duty truck assembly coating facilities. For 

all the operations, except for final repair, the recommended limits are based on data supplied 

by the Alliance of Automobile Manufacturers member companies and non-member 

18 
companies in 2008. 

The recommended limits for electrodeposition primer, primer-surfacer and topcoat 

are more stringent than State rules, most of which are based on the 1977 CTG and or the 

NSPS limits. For final repair operations, no information was presented in the industry 

submittals. Therefore, we chose to recommend the limits for final repair recommended in 

the 1977 CTG. Additionally, an alternative emission limit for combined primer-surfacer and 

topcoat applications is recommended because in some facilities these processes are 

becoming progressively indistinguishable from each other. 

For electrodeposition primer the recommended limit uses the same emission limit 

format as the NSPS. In addition, we recommend that facilities determine the VOC emission 

rate from electrodeposition primer using the same monthly weighted averaging approach as 

that provided in the NSPS. The electrodeposition primer system includes a large dip tank 

which may contain up to 100,000 gallons of coating. Material additions are typically made 

every few days to replenish the system and to maintain the material in the system at a near 

constant mix. During periods of low production, additional solvent may need to be added 

to maintain the system. The NSPS emission limit format and monthly weighted averaging 

approach takes these practices into account. For these reasons, we suggest the NSPS 

emission limit format and monthly weighted averaging approach be used with our RACT 

recommendation for electrodeposition primer. 

For primer-surfacer, topcoat, and combined primer-surfacer and topcoat, the 

recommended limits are expressed as a daily weighted average as determined by following 

the procedures in the revised Automobile Topcoat Protocol. In conjunction with this CTG 

we have revised the Automobile Topcoat Protocol. The revised protocol includes new 

sections on accounting for control of spray booth emissions and instructions for applying the 

protocol to primer-surfacer operations. We recommend that facilities refer to the procedures 

and calculations in the revised protocol for determining the daily VOC emission rate of 

automobile and light-duty truck primer-surfacer and topcoat operations. 

For final repair our recommended limit is expressed as a daily weighted average or an 

occurrence weighted average. An occurrence weighted average is a simplified averaging 

approach for individual repairs. Our recommendation for an occurrence weighted average for 

final repair is to give clear coat a weighting factor of two and give each other coating used in the 

repair a weighting factor of one. For an example, see Bay Area Air Quality Management 

District, Regulation 8 Rule 45, Section 8-45-227, January 6, 1999. 

States may wish to consider the use of longer averaging times for primer-surfacer, 

topcoat, combined .primer-surfacer and topcoat, or final repair. EPA generally recommends 

that States apply R_ACT on.a short-term basis up to 24 hours, h However, EPA has issued 

See, e.g., 52 FR 45108, col. 2, "Compliance Periods" (November 24, 1987). "VOC rules should describe explicitly 

19 
guidance that addresses averaging times !onger than 24 hours under certain conditions, 

The EPA's "Economic Incentive Policy ''J provides guidance on use of long-term averages 

with regard.to RACT and generally provides for averaging times of no greater than 30 days. 

Because of the nature of averaging, however, we recommend that any State RACT Rules 

that allow for averaging include appropriate recordkeeping and reporting requirements. 

"Fable 5. Recommended VOC Emission Limits for Automobile and Light-Duty Truck 

Assembly Coatings 

Assembly Coating Process Recommended VOC Emission Limit 

Electrodeposition primer When solids 

(EDP) operations (including 

application area, spray/rinse 

stations, and curing oven) 

Primer-surfacer operations 

(including application area, 

flash-off area, and oven) 

Topcoat operations (including 

application area, flash-off 

area, and oven) 

Final repair operations 

Combined primer-surfacer 

and topcoat operations 

turnover ratio 

(Rr)>0.16: 

0.084 kg 

VOC/liter (0.7 

lb/gal) coating 

solids applied. 

When 

0.040<Rr<0.160: 

0.084X3500"I60"RT kg 

VOC/liter (0.084x3 500' 160"R 

T 

x 8.34 lb/gal) coating solids 

applied. 

When 

Rr<0.040: 

No VOC 

emission 

limit. 

1.44 kg of VOC/liter of deposited solids (12.0 lbs VOC/gal 

deposited solids) on a daily weighted average basis as 

determined by following the procedures in the revised 

Automobile Topcoat Protocol. a 

1.44 kg VOC/liter of deposited solids (12.0 lb VOC/gal 

deposited solids) on a daily weighted average basis as 

determined by following the procedures in the revised 

Automobile Topcoat Protocol. 

0.58 kg VOC/liter (4.8 lb VOC/.gallon of coating) less water and 

less exempt solvents on a daily weighted average basis or as an 

occurrence weighted average. 

1.44 kg VOC/liter of deposited solids (12.0 lb VOC/gal 

deposited solids) on a daily weighted average basis as 

determined by following the procedures in the revised 

Automobile Topcoat Protocol. 

the compliance timeframe associated with each emission limit (e.g., instantaneous or daily). However, where the 

rules are silent on compliance time, EPA will interpret it as instantaneous." 

Memorandum from John O'Connor, Acting Director of the Office of Air Quality Planning and Standards, January 

20, 1984, "Averaging Times for Compliance with VOC Emission Limits--SIP Revision Policy." 

"Improving Air Quality with Economic Incentive Programs, January 2001," available at 

http ://www.epa.gov/ttn/oarpg/t 1/memoranda/eipfin.pd f. 

20 
Table 6. Recommended VOC Emission Limits for Miscellaneous Materials Used at 

Automobile and Light-Duty Truck Assembly Coating Facilities (grams of VOC per liter of 

coating excluding water and exempt compounds k 

as applied) 

Material Recommended VOC 

Emission Limit 

Automobile and light-duty truck glass bonding primer 900 g VOC/liter 

Automobile and light-duty truck adhesive 250 g VOC/liter 

Automobile and light-duty truck cavity wax 650 g VOC/liter 

Automobile and light-duty truck sealer 650 g VOC/liter 

Automobile and light-duty truck deadener 650 g VOC/liter 

Automobile and light-duty truck gasket/gasket sealing material 200 g VOC/liter 

Automobile and light-duty truck underbody coating 650 g VOC/liter 

Automobile and light-duty truck trunk interior coating 650 g VOC/liter 

Automobile and light-duty truck bedliner 200 g VOC/liter 

Automobile and light-duty truck weatherstrip adhesive 750 g VOC/liter 

Automobile and light-duty truck lubricating wax/compound 700 g VOC/liter 

We are recommending that the VOC emission limits not be applied to materials supplied 

in containers with a net volume of 16 ounces or less, or a net weight of one pound or less. 

We also recommend that the VOC content of coatings, other than reactive adhesives, 

used at automobile and light-duty truck coatings assembly coatings facilities .be determined 

using EPA Method 24. We recommend that the procedure for reactive adhesives in 

Appendix A of the NESHAP for surface coating of plastic parts (40 CFR Part 63, subpart 

PPPP) be used to determine the VOC content of reactive adhesives. In addition, we 

recommend that manufacturer's formulation data be accepted as an alternative to these 

methods. If there is a disagreement between manufacturer's formulation data and the results 

of a subsequent test, we recommend that States use the test method results unless the facility 

can make a demonstration to the States' satisfaction that the manufacturer's formulation data 

are correct. 

Additionally, the CTG recommends work practices to reduce emissions from coating 

operations, such as covering open containers. 

k Exempt compounds are those classified by EPA as having negligible photochemical reactivity as listed in 40 CFR 

51.100(s). Exempt compounds are not considered to be VOC. 

21 
The recommended emission limits for primer-surfacer and topcoat operations can be 

achieved with a combinaiion of higher-solid solvent-borne coatings, efficient application 

equipment and bake oven exhaust control. The primer-surfacer and topcoat operations at many 

facilities are performing significantly better than the recommended emission limits by using 

some combination of powder primer-surfacer, waterborne primer-surfacer or basecoat, and 

partial control of spray booth exhaust (principally from automated spray booth zones). The cost 

and cost-effectiveness of retrofitting or converting a facility using higher-solid solvent-borne 

coatings, efficient application equipment and bake oven exhaust control to one that uses powder 

primer-surfacer, waterborne primer-surfacer or basecoat, or partial control of spray booth 

exhaust, is not believed to be reasonable in the context of RACT. 

B. Work Practices for Coating-Related Activities and Cleaning Materials 

In addition to the control options above, this CTG recommends work practices to further 

reduce VOC emissions from automobile and light-duty truck assembly coating-related activities. 

Although VOC reductions achieved by implementing the work practices that we recommend for 

these coating-related activities may not be quantifiable, they are beneficial to the overall goal of 

reducing VOC emissions. 

We recommend work practices for storage, mixing, and handling operations for coatings, 

thinners, and coating-related waste materials. Specifically, we recommend the following work 

practices: (1) store all VOC-containing coatings, thinners, and coating-related waste materials in 

closed containers; (2) ensure that mixing and storage containers used for VOC-containing 

coatings, thinners, and coating-related waste materials are kept closed at all times except when 

depositing or removing these materials; (3) minimize spills of VOC-containing coatings, 

thinners, and coating-related waste materials; (4) convey VOC-containing coatings, thinners, and 

coating-related waste materials from one location to another in closed containers or pipes; and (5) 

minimize VOC emission from cleaning of storage, mixing, and conveying equipment. 

Additionally, we recommend that each facility develop and implement a work practice 

plan to minimize VOC emissions from cleaning and from purging of equipment associated with 

all coating operations for which emission limits are recommended in this CTG. We recommend 

that the plan specify practices and procedures to ensure that VOC emissions from the following 

operations are minimized: 

Vehicle body wiping; 

Coating line purging; 

Flushing of coating systems; 

Cleaning of spray booth grates; 

Cleaning of spray booth walls; 

Cleaning of spray booth equipment; 

Cleaning external spray booth areas; and 

Other housekeeping measures (e.g., keeping solvent-laden rags in closed containers.) 

The 2004 NESHAP similarly requires development and implementation of a work 

22 
practice plan for reducing HAP emissions. If a facility covered by this CTG already has a 

NESHAP work practice plan in place, instead of creating another work practice plan to address 

VOC emissions, we recommend that the facility simply add to its NESHAP work practice plan 

procedures for minimizing non-HAP VOC emissions. Most elements of the NESHAP work 

practice plan, which is directed at reducing organic HAP, are also consistent with reducing VOC 

emissions. Therefore, there is no need to create another work practice plan to address VOC 

emissions. 

VII. Emission Reductions and Cost Effectiveness of Recommended Control Options 

Based on information supplied by the Alliance of Automobile Manufacturers and other 

manufacturers, we estimated that there are a total of 52 automobile and light-duty truck 

assembly plants in the U.S. Using the 2004 ozone nonattainment designations, we determined 

that 33 of these facilities are in ozone nonattainment areas. The 2002 National Emissions 

Inventory (NEI) contains information for 32 of these 33 facilities. These 32 facilities reported 

actual VOC emissions totaling approximately 19,500 tons in 2002. 

Auto and light-duty truck coating facilities have reduced the VOC emissions from their 

coating operations to comply with the NSPS, NESHAP, and State rules. The recommended 

VOC emission rates described above reflect the control measures that are currently being 

implemented by these facilities. Consequently, there is no additional cost to implement the CTG 

recommendations for coatings. For the same reason, we do not anticipate additional VOC 

emission reduction from coatings. 

The CTG also recommends work practices for reducing VOC emissions from both 

coatings and cleaning materials. We believe that our work practice recommendations in the 

CTG will result in a net cost savings. Implementing work practices reduces the amount of 

coatings and cleaning materials used by decreasing evaporation. 

23 
VIII. References 

Control of Volatile.Organic Emissions from Existing Stationary Sources Volume II: 

Surface Coating of Cans, Coil, Paper, Fabrics, Automobiles, and Light-Duty Trucks. 

Publication No. EPA-450/2-77-008. U. S. Environmental Protection Agency, Research 

Triangle Park, NC. May 1977. The cover page of this document is presented in 

Appendix B. The full document is available as a separate item in docket EPA-HQ-OAR2008-0413 at www.regulations.gov. 

U.S. Environmental Protection Agency. Standards of Performance for Automobile and 

Light-Duty Truck Surface Coating Operations. 40 CFR part 60, subpart MM. 

U.S. Environmental Protection Agency. National Emission Standards for Hazardous Air 

Pollutants: Surface Coating of Automobiles and Light-Duty Trucks. 40 CFR part 63, 

subpart IIII. 

24 
Appendix A 

Definitions 
Definitions 

Adhesive means any chemical substance that is applied for the purpose of bonding two surfaces 

together other than by mechanical means. 

Automobile and light-duty truck adhesive means an adhesive, including glass bonding 

adhesive, used at an automobile or light-duty truck assembly coating facility, applied for the 

purpose of bonding two vehicle surfaces together without regard to the substrates involved. 

Automobile and light-duty truck bedliner means a multi-component coating, used at an 

automobile or light-duty truck assembly coating facility, applied to a cargo bed after the 

application of topcoat and outside of the topcoat operation to provide additional durability and 

chip resistance. 

Automobile and light-duty truck cavity wax means a coating, used at an automobile or lightduty truck assembly coating facility, applied into the cavities of the vehicle primarily for the 

purpose of enhancing corrosion protection. 

Automobile and light-duty truck deadener means a coating, used at an automobile or lightduty truck assembly coating facility, applied to selected vehicle surfaces primarily for the 

purpose of reducing the sound of road noise in the passenger compartment. 

Automobile and light-duty truck gasket/gasket sealing material means a fluid, used at an 

automobile or light-duty truck assembly coating facility, applied to coat a gasket or replace and 

perform the same function as a gasket. Automobile and light-duty truck gasket/gasket sealing 

material includes room temperature vulcanization (RTV) seal material. 

Automobile and light-duty truck glass bonding primer means a primer, used at an automobile 

or light-duty truck assembly coating facility, applied to windshield or other glass, or to body 

openings, to prepare the glass or body opening for the application of glass bonding adhesives or 

the installation of adhesive bonded glass. Automobile and light-duty truck glass bonding primer 

includes glass bonding/cleaning primers that perform both functions (cleaning and priming of the 

windshield or other glass, or body openings) prior to the application of adhesive or the 

installation of adhesive bonded glass. 

Automobile and light-duty truck lubricating wax/compound means a protective lubricating 

material, used at an automobile or light-duty truck assembly coating facility, applied to vehicle 

hubs and hinges. 

Automobile and light-duty truck sealer means a high viscosity material, used at an automobile 

or light-duty truck assembly coating facility, generally, but not always, applied in the paint shop 

after the body has received an electrodeposition primer coating and before the application of 

subsequent coatings (e.g., primer-surfacer). The primary purpose of automobile and light-duty 

truck sealer is to fill body joints completely so that there is no intrusion of water, gases or 

corrosive materials into the passenger area of the body compartment. Such materials are also 

referred to as sealant, sealant primer, or caulk. 

26 
Automobile and light-duty truck trunk interior coating means a coating, used at an 

automobile or light-duty truck assembly coating facility outside of the primer-surfacer and 

topcoat operations, applied to the trunk interior to provide chip protection. 

Automobile and light-duty truck underbody coating means a coating, used at an automobile 

or light-duty truck assembly coating facility, applied to the undercarriage or firewall to prevent 

corrosion and/or provide chip protection. 

Automobile and light-duty truck weatherstrip adhesive means an adhesive, used at an 

automobile or light-duty truck assembly coating facility, applied to weatherstripping materials 

for the purpose of bonding the weatherstrip material to the surface of the vehicle. 

Electrodeposition primer means a process of applying a protective, corrosion-resistant 

waterborne primer on exterior and interior surfaces that provides thorough coverage of recessed 

areas. It is a dip coating method that uses an electrical field to apply or deposit the conductive 

coating onto the part. The object being painted acts as an electrode that is oppositely charged 

from the particles of paint in the dip tank. Also referred to as E-Coat, Uni-Prime, and ELPO 

Primer. 

Final repair means the operations performed and coating(s) applied to completely-assembled 

motor vehicles or to parts that are not yet on a completely assembled vehicle to correct damage 

or imperfections in the coating. The curing of the coatings applied in these operations is 

accomplished at a lower temperature than that used for curing primer-surfacer and topcoat. This 

lower temperature cure avoids the need to send parts that are not yet on a completely assembled 

vehicle through the same type of curing process used for primer-surfacer and topcoat and is 

necessary to protect heat sensitive components on completely assembled vehicles. 

In-line repair means the operation performed and coating(s) applied to correct damage or 

imperfections in the topcoat on parts that are not yet on a completely assembled vehicle. The 

curing of the coatings applied in these operations is accomplished at essentially the same 

temperature as that used for curing the previously applied topcoat. Also referred to as high bake 

repair or high bake reprocess. In-line repair is considered part of the topcoat operation. 

Primer-surfacer means an intermediate protective coating applied over the electrodeposition 

primer and under the topcoat. Primer-surfacer provides adhesion, protection, and appearance 

properties to the total finish. Primer-surfacer may also be called guide coat or surfacer. Primersurfacer operations may include other coating(s) (e.g., anti-chip, lower-body anti-chip, chipresistant edge primer, spot primer, blackout, deadener, interior color, basecoat replacement 

coating, etc.) that is (are) applied in the same spray booth(s). 

Topcoat means the final coating system applied to provide the final color and/or a protective 

finish. The topcoat may be a monocoat color or basecoat/clearcoat system. In-line repair and 

two-tone are part of topcoat. Topcoat operations may include other coating(s) (e.g., blackout, 

interior color, etc.) that is (are) applied in the same spray booth(s). 

27 
Solids turnover ratio (RT') means the ratio of total volume of coating solids that is added to the 

EDP system in a calendar month divided by the total volume design capacity of the EDP system. 

28 
Appendix B 

1977 CTG for Surface Coating of Cans, Coils, Paper, Fabrics, Automobiles, and LightDuty Trucks 

The cover page of this document is presented here. The full document is available as a 

separate item in docket EPA-HQ-OAR-2008-0413 at www.regulations.gov. 

29 
EPA-450/2-77.006 

.May 1977 

(OAQPS NO. 1.2-073) 

OAqPS 

CAN COAT I •G 

AP- 4• 

S•¢t io. 4.2.2.¢ 

GUIDELINES 

CONTROL OF VOLATILE 

ORGANIC EMISSIONS 

FROM- EXISTING 

STATIONARY SOURCES. 

VOLUME II: SURFACE COATING 

OF CANS, COILS, PAPER, 

FABRICS, AUTOMOBILES, 

•;••:•:•=:.•:AND LIGHT-DUTY TRUCKS 

U.S, ENVIRONMENTAL PROTECTION AGENCY 

Office of Air and Waste Management 

Office of Air Quality Planning and Standards 

Research Triangle Park, North Carolina 27711 

 ̧30 
Appendix C 

Summary of Selected State Regulations for Automobile and Light-Duty Truck Assembly 

Coatings (including Bay Area AQMD) 

31 

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