SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT 

Staff Report for 

PROPOSED AMENDED RULE 1151 – MOTOR VEHICLE AND MOBILE 

EQUIPMENT NON-ASSEMBLY LINE 

COATING OPERATIONS 

December 2005 

Deputy Executive Officer 

Planning, Rule Development, & Area Sources 

Elaine Chang, DrPH 

Assistant Deputy Executive Officer 

Planning, Rule Development, & Area Sources 

Laki T. Tisopulos, Ph.D., P.E. 

Planning and Rule Manager 

VOC Rule Development 

Larry Bowen, P.E. 

Author: Ricardo A. Rivera, Air Quality Specialist 

Reviewed by: Ed Muehlbacher, P.E., Program Supervisor 

 Frances Keeler, Senior Deputy District Counsel 

Technical Assistance: Steve Jones, A.Q. Analysis and Compliance Supervisor 

 James Koizumi, Air Quality Specialist 

 Patricia Kwon, Air Quality Specialist 

 Helmy Sultan, Ph.D., Air Quality Specialist 

 Elizabeth Dooley, Student Intern
SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT 

GOVERNING BOARD 

Chair: WILLIAM A. BURKE, Ed.D. 

 Speaker of the Assembly Appointee 

Vice Chair: S. ROY WILSON, Ed.D. 

 Supervisor, Fourth District 

 Riverside County Representative 

MEMBERS:

MICHAEL D. ANTONOVICH 

Supervisor, Fifth District 

Los Angeles County Representative 

JANE W. CARNEY 

Senate Rules Committee Appointee 

BEATRICE J. S. LAPISTO-KIRTLEY 

Mayor, City of Bradbury 

Cities Representative, Los Angeles County/Eastern Region 

RONALD O. LOVERIDGE 

Mayor, City of Riverside 

Cities Representative, Riverside County 

GARY OVITT 

Supervisor, Fourth District 

San Bernardino County Representative 

JAN PERRY 

Councilmember, 9th District 

Cities Representative, Los Angeles County, Western Region 

MIGUEL PULIDO 

Mayor, City of Santa Ana 

Cities Representative, Orange County 

JAMES SILVA 

Supervisor, Second District

Orange County Representative 

CYNTHIA VERDUGO –PERALTA 

Governor’s Appointee 

DENNIS YATES 

Mayor, City of Chino 

Cities Representative, San Bernardino County 

 EXECUTIVE OFFICER

BARRY R. WALLERSTEIN, D.Env. 
TABLE OF CONTENTS

EXECUTIVE SUMMARY .....................................................................................1 

BACKGROUND .....................................................................................................3 

PROCESS DESCRIPTION .....................................................................................4 

COATINGS AVAILABLE TO MEET THE PROPOSED LIMITS.......................6 

ALTERNATIVE CONTROLS................................................................................7 

PROPOSED AMENDMENTS................................................................................8 

AFFECTED SOURCES/EMISSIONS INVENTORY..........................................12 

EMISSION REDUCTIONS ..................................................................................14 

COST AND COST-EFFECTIVENESS ................................................................15 

INCREMENTAL COST-EFFECTIVENESS .......................................................18 

COMPARATIVE ANALYSIS..............................................................................19 

DRAFT FINDINGS...............................................................................................19 

PUBLIC COMMENTS AND RESPONSES.........................................................20 

REFERENCES ......................................................................................................24 
Staff Report for Proposed Amended Rule 1151 

FSR - 1 - December 2005 

EXECUTIVE SUMMARY 

Rule 1151 – Motor Vehicle and Mobile Equipment Non-Assembly Line Coating Operations was 

adopted by the South Coast Air Quality Management District (AQMD) Governing Board on July 

8, 1988, to control volatile organic compound (VOC) emissions from motor vehicle and mobile 

equipment non-assembly line coating operations. Rule 1151 applies to both commercial and 

noncommercial refinishing coating applications that include, but are not limited to auto body 

repair/paint shops, production auto body paint shops, new car dealer repair/paint shops, fleet 

operators repair/paint shops, custom-made car fabrication facilities, truck body builders, and any 

other motor vehicle or mobile equipment non-assembly line painting operation. (Motor vehicle 

assembly line coating operations are subject to AQMD Rule 1115). Rule 1151 establishes VOC 

limits by coating category and vehicle type (Group I and Group II vehicles). Group I vehicles 

include large-sized trucks, buses and mobile equipment. Group II vehicles include passenger 

cars, small-sized and medium-sized trucks and vans, motor homes, and motorcycles. 

The objective of Proposed Amended Rule (PAR) 1151 is to implement portions of the 2003 Air 

Quality Management Plan (AQMP) Control Measure CTS-10 – Miscellaneous Industrial 

Coatings and Solvent Operations. Staff used the 2005 California Air Resources Board (CARB) 

Suggested Control Measure (SCM) for Automotive Refinishing Coatings1 in the development of 

the proposed amendments. The final staff proposal may be amended to reflect the final SCM 

adopted by CARB. 

The proposed amendments modify Rule 1151 coating categories and VOC limits in accordance 

with CARB’s 2005 Automotive Refinishing SCM. Specifically, the proposed amendments: (1) 

Combine Group I and Group II vehicle categories and establish VOC limits by coating category 

only; (2) Eliminate the composite VOC limit for multistage coating systems and establish 

independent VOC limits for both the color and clear parts of the multistage coating system; (3) 

Combine the primer, primer surfacer, and primer sealer categories and establish a single VOC 

limit for primers; and (4) Eliminate the general specialty coating category and replace it with 

specific categories, and VOC limits. 

The new VOC limits proposed in Rule 1151 are essentially identical to the VOC limits being 

proposed in the CARB 2005 Automotive Refinishing SCM. According to information generated 

by CARB, with the exception of the VOC limits proposed for adhesion promoters and 

pretreatment coatings, the VOC limits proposed for new coating categories are based upon 

products that are currently available in the marketplace in the United States and/or other parts of 

the world. 

Although the proposed amendments are technology neutral, the proposed VOC limit for basecoat 

(color coating) is based on waterborne technology. There are waterborne products currently 

available in the marketplace; however, the use of the technology in Southern California has been 

limited. The transition to waterborne technology in the refinishing industry is eminent. The 

European Union is implementing waterborne technology in 2007 as part of the European 

 

1

 Proposed Suggested Control Measure for Automotive Coatings, CARB 2005 
Staff Report for Proposed Amended Rule 1151 

FSR - 2 - December 2005 

Parliament directive2 to reduce VOC emission from coatings and solvents. Furthermore, CARB 

and AQMD staff have received information from coating manufacturers that the automotive 

coating industry is likely to rely on waterborne technology to comply with the proposed VOC 

limits. 

According to information given to CARB, most automotive coating manufacturers believe that 

the VOC limit proposed for basecoat or color coat in the SCM is feasible provided sufficient 

time is given to prepare for the implementation of waterborne technology in California. To this 

end, the VOC limits for color and clear coatings in PAR 1151 are proposed to become effective 

by July 1, 2008 with a sell-through provision of six months that requires full implementation of 

the proposed VOC limits on January 1, 2009. The VOC limits for adhesion promoters, primer, 

and single-stage coatings become effective January 1, 2010. The VOC limits for all other 

categories are proposed to become effective January 1, 2009. 

The proposed amendments also add, in accordance with the CARB SCM, a prohibition of 

possession that will prohibit possession of non-compliant coatings unless specific conditions are 

met. The prohibition of possession is proposed to become effective six months after adoption of 

the proposed rule. 

Finally, the proposed amendments also add language to the rule that exempts tertiary butyl 

acetate (TBAc) as a VOC for Rule 1151 operations on a limited basis. This limited exemption 

deviates from the SCM recommendation that exempts TBAc as a VOC for all automobile 

refinish coatings. The California Environmental Protection Agency (Cal/EPA) conducted an 

environmental impact assessment (EIA) pursuant to California Environmental Quality Act 

(CEQA) to determine the environmental impacts associated with granting an exemption for 

TBAc as a VOC in the CARB Consumer Products Regulation. (Environmental Impact 

Assessment of Tertiary-Butyl Acetate, June 2006). CARB concluded that there were no 

significant impacts statewide associated with the exemption of TBAc as a VOC in the definition 

in the CARB Consumer Products Regulation. The EIA further recommended that local 

regulatory agencies conduct their own analysis prior to exempting TBAc as a VOC in any 

applicable rule. As a result, CARB staff after their analysis recommended in the SCM that 

TBAc be exempt as a VOC for all automotive refinish coatings. At the federal level, TBAc was 

recently delisted as a VOC by U.S. EPA due to its low photochemical reactivity. As part of the 

federal delisting of TBAc, the manufacturer of TBAc committed itself to work with U.S. EPA to 

conduct the additional toxicity testing necessary to resolve the long-term toxicity uncertainty of 

TBAc. As recommended by CARB, the District has issued a Draft Environmental Assessment 

for PAR 1151. The Draft Environmental Assessment is based on the health analysis provided by 

Cal/EPA but uses a worst-case scenario in assessing potential carcinogenic risk. The analysis of 

the Draft Environmental Assessment examines the staff recommendation that TBAc use be 

limited to coating categories other than clear and color coatings. Staff believes that there are 

sufficient compliant coatings available on the market in the clear and color coating categories 

that will meet the VOC limits of the rule without the use of TBAc. However, in other categories 

the use of TBAc is warranted to ensure the development of lower VOC coatings. The Draft 

Environmental Assessment concludes that the limited use of TBAc would result, for the largest 

 

2

 Directive 2004/42/CE of the European Parliament and of the council. 
Staff Report for Proposed Amended Rule 1151 

FSR - 3 - December 2005 

automobile refinishing facility in the AQMD, in an estimated carcinogenic risk of five in one 

million, which is lower than the significance threshold of 10 in one million for CEQA. Acute 

and chronic hazard indices were also estimated to be less than the significance threshold of 1.0. 

Furthermore, the rule includes a commitment to conduct a technical assessment on the use of 

TBAc by July 1, 2007. Upon completion of this technical assessment, staff will report back to 

the Board on the appropriateness of maintaining TBAc as a non-VOC. The proposed limited 

exemption will maintain the potential risk at low levels, while providing some level of flexibility 

in developing compliant coatings. 

Historically, the AQMD has identified approximately 3,500 business that use automotive 

coatings. However, AQMD records indicate that there are only approximately 1,730 commercial 

refinishing facilities with permits to construct and operate spray booths. The remaining facilities 

are believed to use or handle automotive coatings on a limited basis. The emissions inventory 

for this source category is 10.3 tons per day (tpd). 

The proposed amendments will result in VOC emission reductions of 3.7 tpd, which represent a 

reduction of approximately 36 percent from current emission levels. The cost-effectiveness for 

the proposed amendments to Rule 1151 is estimated at $2,291 per ton of VOC reduced. 

BACKGROUND 

Rule 1151 has been amended 11 times since its 1988 adoption and currently regulates VOCs, as 

well as, stratospheric ozone-depleting and global warning compounds, and carcinogenic 

(cadmium and hexavalent chromium) emissions from non-assembly vehicle and mobile 

equipment refinishing operations. Motor vehicle assembly line coating operations are regulated 

under Rule 1115 – Motor Vehicle Assembly Line Coating Operations. 

Rule 1151 was first amended on May 5, 1989, to incorporate Rule 109 recordkeeping 

requirements. The rule was amended again on March 2, 1990, along with the adoption of Rule 

108 – Alternative Emission Control Plans for consistency. Other amendments to 1151 followed 

that same year on June 1, November 2, and December 7, 1990 to incorporate equivalent methods 

of equipment cleaning, phase out aerosol spray can usage in touch-up coatings, and make the 

rule language consistent with other adopted rules, respectively. On August 2, 1991 the rule was 

again amended as part of the adoption of Rule 1171 – Solvent Cleaning Operations. 

On September 6, 1991, Rule 1151 underwent the most significant revision to date in response to 

the automotive refinishing industry’s concerns regarding coating technology and enforceability. 

The September 6, 1991, amendment added new coating categories, restructured VOC limits and 

adjusted compliance dates. Specifically, the categories added to the rule as part of this 

amendment included primer surfacer, primer sealer, multistage, metallic iridescent, and specialty 

coatings. The September 6, 1991 amendments contained technology-forcing VOC limits that 

were to become effective on January 1995. However, the rule was again amended on December 

9, 1994, to delay the implementation of the 1995 limits by two years to January 1997. The 1994 
Staff Report for Proposed Amended Rule 1151 

FSR - 4 - December 2005 

amendments to the rule also included language corrections and other administrative changes 

requested by United States Environmental Protection Agency (U.S. EPA). 

On June 13, 1997, the rule was amended to correct State Implementation Plan (SIP) deficiencies, 

improve rule language and other administrative amendments to make the rule consistent with 

changes made to other AQMD rules. Rule 1151 was last amended on December 11, 1998, to 

delay the implementation of VOC limits for Group II multistage topcoat; exempt topcoats used 

on prototype vehicles from VOC limits, add a usage limitation for specialty coatings, and extend 

the applicability of the prohibition of sale, offer for sale, and distribution requirements. The last 

amendment to the rule also included language clarifications as well as other administrative 

changes. 

Recent Developments 

Coating manufactures have expressed dissatisfaction with the lack of uniformity of air quality 

regulations that apply to the automotive refinishing industry within California. At issue are the 

different VOC limits, how coating categories are defined, and varying rule interpretations that 

exist throughout the state. These variations make it difficult for coating manufactures to create 

and sell products statewide that are in compliance with current applicable district rules. In 

November 2000, CARB proposed the development of a statewide automotive coating operations 

suggested control measure to address the concerns of coating manufacturers. In response to this 

proposal, the California Air Pollution Control Officer’s Association (CAPCOA) assembled the 

CAPCOA Enforcement Automotive Coating Working Group and developed a model rule for 

automotive coating operations to be used by each of the air pollution control agencies within the 

state of California in lieu of a statewide rule. The model rule was intended to provide the desired 

uniformity to the automotive refining industry. The final draft rule was issued by the 

Enforcement Automotive Coating Working Group in 2002. 

To provide a mechanism to formalize the model rule, CARB is in the process of developing a 

SCM for Automotive Refinishing. CARB is collaborating with California’s air districts on the 

SCM, which is scheduled for a public hearing in October 2005. 

PROCESS DESCRIPTION

Rule 1151 is applicable to automotive and mobile equipment refinishing operations. Automotive 

coatings are applied to motor vehicles and mobile equipment to protect and enhance the 

appearance of exterior surfaces. In terms of the use of coatings materials, the automotive 

refinishing industry consists of the application of coatings at any time subsequent to the initial 

manufacturing process. Automotive refinishing products are applied as part of a repair process 

following accidental damage to a vehicle to rectify damage or errors that occur during 

manufacturing or in transit or to change the appearance or color of a vehicle. Refinishing 

facilities include five broad categories: auto body repair/paint shops, production auto body paint 

shops, new car dealer repair/paint shops, fleet operators repair/paint shops, and truck bodybuilders. 

Refinishing may be done on a spot, a panel, or the entire vehicle or mobile equipment. Spot 

repair and paint work is generally performed on a small damaged area. The repair work would 
Staff Report for Proposed Amended Rule 1151 

FSR - 5 - December 2005 

generally include the physical repair of the damaged area, conditioning of substrate and 

application of undercoats and topcoats. Panel repair is similar of that of a spot work except that 

the work area is larger it may include a hood or a door for example. Overall work, as the word 

implies, involves the refinishing of the entire body. Overall work may be performed to repair a 

faded color on an automobile or piece of equipment or to change the color of the vehicle. 

Therefore, refinishing operations, in term of application of coatings, refers to the activity of 

restoring a vehicle’s finish to its original condition as well as to the activity of repainting an 

entire vehicle to change or enhance its appearance. 

Refinishing Industry Coatings 

There are two main classes of automotive coatings: undercoats and topcoats. Undercoats 

including, primers, primer surfacers, and primer sealers prepare the exterior surfaces by 

providing corrosion resistance, adhesion and a smooth foundation for subsequent topcoats. 

Topcoats are applied to provide color, gloss, and a protective finish. Topcoats can be classified 

into three main categories: (1) single-stage solid color or mono-coats, (2) single-stage metallic 

finish, and (3) multistage systems. 

Single-stage topcoats consist of only one final coating, which is applied over undercoats to 

provide color, gloss, and protection. The difference in the single-stage solid color and the single 

stage-metallic finish is that the solid colors do not contain any metal flakes. 

Multistage coatings, unlike the conventional single-stage coatings, consist of two or more layers, 

each contributing separately to the final finish’ characteristics. The initial layer, or basecoat 

layer, contains the pigmentations and metallic flakes that provide the final color and color 

effects. Multistage coatings include two-stage systems as well as three-stage systems. Threestage coatings differ from the two stage-systems in that it includes a midcoat layer that provides 

additional color effects, such as a pearlized light effect resulting from mica flakes. The final 

coatings in multistage systems are non-pigmented clear coats that provide hardness and 

durability to the final finish. The nature of the coating systems requires that all coating 

components be used to refinish the vehicle in order to provide the required appearance and 

performance. 

The main difference in the application of coatings in a manufacturing setting to that of a 

refinishing environment are the curing characteristics of the coatings. Automotive original 

equipment manufacturing (OEM) coatings are typically cured by the use of baking ovens that 

operate at high temperatures. The types of coatings used in refinishing operations are typically 

air dry, cured with the aid of infrared lamps, or by forced-air spray booths. Refinishing shops 

cannot use high temperature ovens due to the potential damage to other automobile components 

made of plastic or other materials that may be damaged at high temperatures. Therefore, 

automotive refinishing coatings are formulated for faster drying times. 
Staff Report for Proposed Amended Rule 1151 

FSR - 6 - December 2005 

COATINGS AVAILABLE TO MEET THE PROPOSED VOC LIMITS 

The proposed coating categories and the corresponding VOC limits are essentially identical to 

the categories and VOC limits proposed under the 2005 CARB Automotive SCM. In developing 

the revised coating categories and VOC limits for the Automotive SCM, CARB staff considered 

the results of the 2002 Automotive Refinishing Coatings survey; information from automotive 

refinishing coating manufacturers, solvent suppliers, and other industry groups; the existing 

VOC limits for automotive refinishing coatings; and, the results of CARB’s technical analysis 

that included the review of trade journals and other literature related to product information. 

Based on their review, CARB staff has concluded that the proposed VOC limits are 

technologically and commercially feasible for full implementation by January 1, 2009. With the 

exception of two coating categories, adhesion promoter and pretreatment coatings, CARB has 

concluded that there are compliant products currently available in the market place to meet the 

proposed VOC limits. However, CARB also believes based on information received from 

coating manufacturers as part of the public review process of the SCM, that compliant 

pretreatment and adhesion promoters coatings will be available in the market place prior to the 

2009 implementation date. AQMD staff has received similar information from a local coating 

manufacturer stating that their company is working on having compliant pretreatment coatings in 

the market place by 2006. 

Approximately 90 percent of the emission reductions associated with the proposed amendments 

are due to the lowering of the VOC limit for basecoat or the color portion of the multistage 

coating systems. The proposed amendments to Rule 1151 are technology neutral. Exempt 

compounds and waterborne technology are the predominant technologies for automotive 

refinishing, however ultraviolet (UV) technology is making inroads and may be used as a 

potential alternative technology. However, the coating manufacturers have stated that the most 

likely technology that would be use to comply with the VOC limit for color coating is 

waterborne technology. Although used in a very limited basis in California, waterborne 

technology is available that meets the proposed limits. Waterborne basecoats have been used in 

Europe for many years and are being mandated there as of January 1, 2007 (CARB 2005). 

Coating manufacturers have stated that additional color development is required before the 

waterborne technology currently used in Europe before it can be fully introduced into California. 

For this reason, the proposed compliance schedule has been set for July 1, 2008 with a sellthrough provision until December 31, 2008. 

Table 1 – Current Compliant Coatings Summary, provides a summary of coatings that comply 

with the proposed VOC limits. The information presented in Table 1 was generated based on 

information received from CARB. CARB generated this information based on data submitted by 

major automotive refinishing coating manufacturers as part of the 2002 automotive refinishing 

survey. The coating manufacturers that submitted information included, Akzo-Nobel, Bondo, 

BASF, Cumberland, DuPont, Earl Scheib, Ellis Paint, Fibre Glass – Evercoat, Hentzen, JonesBlair, Magni, Montana Products, PPG, Sherwin Williams, Spies Hecker, Standox, and Valspar. 

The information presented in the Table 1 is limited to the coating categories that are affected by 

the proposed amendments to Rule 1151. 
Staff Report for Proposed Amended Rule 1151 

FSR - 7 - December 2005 
Staff Report for Proposed Amended Rule 1151 

FSR - 8 - December 2005 

Table 1 – Current Compliant Coatings Summary 

(CARB Data, 2005) 

Number of Companies that: Companies With 

Compliant 

Coatings 

VOC 

(g/l) 

Coating 

Category Sold Type of 

Coating in CA 

Reported 

Compliant 

Mixtures(1)

Adhesion 

Promoter 

5 0 (3) (3) 

Akzo-Nobel < 420 

PPG < 420 

Spies Hecker < 420 

Standox North 

America 

< 420 

Color Coating(2) 12 5 

Valspar < 400 

Pretreatment 

Coatings 

13 0 (3) (3) 

Primer (Primer 

Sealer) 

15 12 Ellis Paint 250 

Single-Stage Spies Hecker 331 

Coating(2)

13 1 

Ellis Paint 336 

Temporary 

Protective 

Coating 

2 1 Ellis Paint 34 

Truck Bed 

Liner Coating 

1 1 Fibre Glass Evercoat 278 

Underbody 

Coating 

3 1 Akzo-Nobel 46 

 Fibre Glass Evercoat 404 

Uniform Finish 

Coating 

5 2 PPG 524 

(1) Valid mixtures (coatings) that meet the proposed VOC limits. 

(2) The mixtures (coating) for the color coating and single stage categories where reported as 

systems and not individual mixtures. 

(3) At this time there are no compliant coatings available for these categories. 

ALTERNATIVE CONTROLS 

In general, the most widely used method for control of surface coating VOC emissions is 

modifying the chemistry of the coating material to reduce the VOC content of the coating. 

Improvement in application methods to improve transfer efficiency can also reduce VOC 

emissions. The use of add-on controls is another method for VOC reduction that has been used 

in surface coating applications. 
Staff Report for Proposed Amended Rule 1151 

FSR - 9 - December 2005 

The use of add-on control technology requires that VOC-laden air from process areas or 

emissions points be captured and directed to air pollution control equipment. The effectiveness 

of an add-on control system is based on the capture efficiency and the VOC destruction 

capability of the emissions control device. Capture efficiency refers to the ability of a ventilation 

system to capture and transfer VOC released from process areas or emission points to the 

pollution control device. If the process areas or emission points meet the criteria set forth in U.S. 

EPA Method 204, the area or emission point may be considered a permanent total enclosure 

(PTE) and the capture efficiency is assumed to be 100 percent. If the criteria of U.S. EPA 

Method 204 is not met then source testing must be performed to determine the capture efficiency 

of the system. 

The options for control devices are numerous, each having different cost and control efficiencies. 

The selection is dependant upon the needs of the specific facility. Although there are many types 

of control devices that work on different principles such as adsorption or destruction of VOC 

emissions, the most typical type of control equipment for the control of VOC emissions is the 

use of thermal destruction equipment such as a thermal oxidizer or a catalytic oxidizer. 

Rule 1151 allows use of add-on control equipment as an option for achieving compliance. 

Although this method of control may be most effective for some operators, it could be 

prohibitively expensive for others, particularly those that are small businesses or have low 

throughputs. Therefore, the use of add-on controls is offered as an option rather than a mandated 

requirement. 

PROPOSED AMENDMENTS 

The proposed amendments modify the rule coating categories and VOC limits in accordance 

with the CARB SCM. Specifically, the proposed amendments: (1) combine Group I and Group 

II vehicle categories and establish VOC limits by coating category only; (2) eliminate the 

composite VOC limit for multistage systems and establish independent VOC limits for both the 

color and clear parts of the multistage coating system; (3) combine the primer, primer surfacer, 

and primer sealer categories and establish a single category and VOC limit for primers; and, (4) 

eliminate the specialty coating category and replace it with specific categories and VOC limits. 

Table 2 – Current and Proposed Coating Categories, below provides a summary of the existing 

and proposed coating categories and VOC limits for the main coating categories in Rule 1151. 

Table 3 – Current and Proposed Coating Categories - Specialty Coatings, provides a summary of 

the current and proposed categories and VOC limits for specialty coatings. 
Staff Report for Proposed Amended Rule 1151 

FSR - 10 - December 2005 

Table 2 – Current and Proposed Coating Categories 

Existing Coating Existing VOC Limit (lbs/gal) 

Category Group I1

 Group II2

Proposed Coating 

Category 

Proposed 

VOC Limit 

(lbs/gal) 

Pretreatment 

Pretreatment 6.5 6.5 Pretreatment 5.5 

Primers 

Primer 2.1 2.1 

Primer Surfacer 2.1 2.1 

Primer Sealer 2.1 2.8 

Primer 2.1 

Topcoats 

General 2.83 3.5 

Metallic/Iridescent 2.8 3.5 

Single Stage 

Coating 

2.8 

Multi-Colored 5.7 5.7 Multi-Colored 5.7 

Color Coating 3.5 Multistage 2.83 4 3.5 

Clear Coating 2.1 

1 Group I Vehicles include large trucks, buses and mobile equipment. 

2 Group II Vehicles include passenger cars, small-sized trucks and vans, medium-sized trucks and 

vans, motor homes, and motorcycles. 

3 The VOC limit for sporty repairs on Group I Vehicles is 3.5 lb/gal. 

4 Assuming a 2.1 lbs/gal clear coating VOC limit, the existing color coating VOC limits are 4.2 

and 6.3 lbs/gal for Group I and II vehicles, respectively. 
Staff Report for Proposed Amended Rule 1151 

FSR - 11 - December 2005 

Table 3 – Current and Proposed Categories – Specialty Coatings 

Existing Coating Existing VOC Limit (lbs/gal)

Category Group I Group II 

Proposed Coating 

Category 

Proposed 

VOC Limit 

(lbs/gal) 

Specialty Coatings 

Adhesion 

Promoters 

7.0 7.0 Adhesion Promoter 4.5 

Uniform Finish 

Blenders 

7.0 7.0 Uniform Finishing 

Coating 

4.5 

Primer 

(Plastic/Flexible 

Primers) 

Elastomeric 2.1 

Materials 

7.0 7.0 

Clear Coat 

(Elastomeric 

Clears) 

2.1 

Anti-Glare Safety 

Coating 

7.0 7.0 Any other Coating 2.1 

Impact Resistant 

Coating 

7.0 7.0 Any other Coating 2.1 

Rubberized 

Asphaltic 

underbody Coating 

7.0 7.0 Underbody Coating 3.6 

Water Holdout 

Coating 

7.0 7.0 Any other Coating 2.1 

Weld Thru 

Coatings 

7.0 7.0 Any other Coating 2.1 

Bright Metal Trim 

Repair Coating 

7.0 7.0 Any Other Coating 2.1 

Other 

Not Currently in 

Rule 1151 

 Truck Bed Liner 

Coating 

2.6 

The proposed amendments also add, in accordance with the SCM, a prohibition of possession 

that will prohibit possession of non-compliant coatings unless specific conditions are met. This 

prohibition will improve the enforceability of the rule by discouraging the unlawful use of noncompliant coatings. Further, the proposed rule language and structure of the rule has also 

changed to reflect the content of the CARB SCM. The modified coating categories and VOC 

limits for color and clear coatings are proposed to be effective on July 1, 2008, with a sellthrough provision in effect until January 1, 2009. This transitional period will allow users to 

become familiar with use of the new coating technologies with less impact to their ongoing 

operations. Consistent with the adopted SCM, the VOC limits for adhesion promoters, primers, 

and single-stage coatings are proposed to become effective January 1, 2010. The VOC limits for 

all other categories are proposed to become effective January 1, 2009. The prohibition of 

possession is to become effective July 1, 2006. 
Staff Report for Proposed Amended Rule 1151 

FSR - 12 - December 2005 

Finally, the proposed amendments also add language to the rule that exempts tertiary butyl 

acetate (TBAc) as a VOC for Rule 1151 operations on a limited basis. This limited exemption 

deviates from the SCM recommendation that exempts TBAc as a VOC for all automotive 

refinish coatings. Cal/EPA conducted an EIA pursuant to CEQA to determine the environmental 

impacts associated with granting an exemption for TBAc as a VOC the CARB Consumer 

Products Regulation. The EIA was performed as a collaborative effort that involved CARB, 

OEHHA, the SWRCB and the DTSC. The EIA for TBAc concluded that the data concerning the 

adverse health effects from exposure to TBAc were limited; and therefore, it is not possible to 

characterize the potential for non-cancer health effects resulting form the potential exposures. 

However, because a metabolite, TBA, has been shown to induce tumors in both rats and mice, 

exposure to TBAc may result in a cancer risk to humans if indeed a significant amount 

metabolizes into TBA. As part of the EIA work for TBAc, an inhalation unit risk factor for TBA 

was derived using TBA data. This inhalation unit risk factor was used to determine the 

carcinogenic risk of using TBAc by OEHHA. CARB concluded that there were no significant 

impacts statewide associated with exemption of TBAc as a VOC in the definition in the CARB 

Consumer Products Regulation. Following this recommendation and using the information 

contained in the Cal/EPA EIA for TBAc, CARB staff, in the development of the SCM, 

conducted a health risk assessment for TBAc using an assumption that TBAc would replace 50 

percent of toluene, xylene and MEK in automotive coatings. Their health risk assessment 

indicated a potential cancer risk of 2.8 in one million. Based on the results of their health risk 

assessment and the potential health benefits due to the low photochemical reactivity of TBAc, 

the SCM recommended that TBAc be exempt as a VOC for all automotive refinish coatings. At 

the federal level, TBAc was recently delisted as a VOC by U.S. EPA due to it’s low 

photochemical reactivity. As part of the federal delisting of TBAc the manufacturer of TBAc 

committed itself to work with U.S. EPA to conduct the additional long-term toxicity testing 

necessary to resolve the toxicity uncertainty of TBAc. As recommended by CARB, the District 

has issued a Draft Environmental Assessment for PAR 1151. The Draft Environmental 

Assessment is based on the health analysis provided by Cal/EPA but uses a worst-case scenario 

in assessing potential carcinogenic risk. The analysis of the Draft Environmental Assessment 

examines the staff recommendation that TBAc use be limited to coating categories other than 

clear and color coatings. Staff believes that there are sufficient compliant coatings available on 

the market in the clear and color coating categories that will meet the VOC limits of the rule 

without the use of TBAc. However, in other categories the use of TBAc is warranted to ensure 

the development of lower VOC coatings. The Draft Environmental Assessment concludes that 

the limited use of TBAc would result, for the largest automobile refinishing facility in the 

AQMD, in an estimated carcinogenic risk of five in one million, which is lower than the 

significance threshold of 10 in one million for CEQA. Acute and chronic hazard indices were 

also estimated to be less than the significance threshold of 1.0. The Draft EA concludes that use 

of TBAc exemption would result for the largest automobile refinishing facility in the AQMD, in 

an estimated carcinogenic risk to the nearest residential receptor of five in one million, which is 

lower than the significance threshold of 10 in one million for CEQA. Acute and chronic hazard 

indices were also estimated to be less than the significance threshold of 1.0. As can be seen in 

Graph 1, below the potential carcinogenic risk to the nearest residential receptor for 

approximately 90 percent of the facilities subject to PAR 1151 is estimated to be less than one in 

one million. 
Staff Report for Proposed Amended Rule 1151 

FSR - 13 - December 2005 

Furthermore, the rule includes a commitment to conduct a technical assessment on the use of 

TBAc by July 1, 2007. Upon completion of this technical assessment, staff will report back to 

the Board on the appropriateness of maintaining TBAc as a non-VOC. The proposed limited 

exemption will maintain the potential risk at low levels, while providing some level of flexibility 

in developing compliant coatings. To conduct its analysis AQMD is planning to review the 

further toxicity testing that the manufacturer of TBAc proposed as part of the federal delisting of 

TBAc. The manufacturer of TBAc was to perform toxicity testing to resolve the current 

uncertainty as it relates to TBAc toxicity and to submit those results to a scientific independent 

peer review panel to determine if additional testing was warranted. 

Graph 1 – Carcinogenic Risk of the TBAc Exemption per Facility Grouping 

0

200

400

600

800

1000

1200

1400

1600

1800

5 > 1 < 5 < 1

Carcinogenic Risk in a Million

Number of Facilities

AFFECTED SOURCES/EMISSIONS INVENTORY 

There are approximately 3,500 facilities in the AQMD that use or handle automotive coatings. 

Approximately 1,700 facilities are fully dedicated to refinishing operations that currently operate 

approximately 2,500 spray booths under AQMD permit. The remaining facilities are believed to 

apply primer and single stage coatings without the use of a spray booth. The facilities that make 

up the refinishing industry include: auto body repair/paint shops, production auto body paint 

shops, new car dealer repair/paint shops, fleet operators repair/paint shops, custom-made car 

fabrication facilities, and truck body builders. 
Staff Report for Proposed Amended Rule 1151 

FSR - 14 - December 2005 

The 2005 emissions inventory for this source category is estimated at 10.3 tpd. The 2010 

emission inventory for 2010 is estimated at 11.2 tpd. The emissions inventory is based on the 

2001 Survey of Automotive Refinish Coatings conducted by CARB. The emissions estimate for 

the AQMD was derived by adjusting the VOC emissions estimate for the State of California, 

approximately 20.7 tons per day (Ref. 2), using the regional population factors of 46 percent of 

the state population, and AQMP emission growth factors to correct the 2001 CARB data to 2005 

inventory. The AQMD inventory calculates to be 7,519,000 lbs/year or 10.3 tons per day. The 

VOC emissions inventory for refinishing operations in the AQMD is comprised of three main 

coating categories: emissions from undercoats, topcoats, and specialty coatings. Tables 4, 5 and 

6, provide the emissions percent distribution for each of the coating categories broken out by the 

relative contribution of Group I and Group II vehicle categories in the existing rule. The 

emissions distribution presented in Tables 4, 5, and 6 was developed on information from 

previous Rule 1151 inventories as well as available AQMD permit and annual emissions data, 

and reflects the relative percentage contribution of each coating category in the current emissions 

inventory. For example, the baseline emission inventory for pretreatment coatings (150,380 

lbs/year) was calculated by multiplying the total current emissions inventory (10.3 tpd or 

7,519,000 lbs/year) by the 2.0 percent contribution of pretreatment coating to the total inventory 

(0.2 and 1.8 percent for Group I and Group II vehicles, respectively). 

Table 4 - Emissions Inventory Percent Distribution - Undercoats 

Coating Category Percent Contribution for 

Group I Vehicles 

Percent Contribution for 

Group II Vehicles 

Primer 0.2 1.5 

Primer Surfacer 0.4 3.4 

Primer Sealer 0.2 2.3 

Pretreatment 0.2 1.8 

Subtotal 1.0 9.0 

Total 10.0 

Table 5 – Emissions Inventory Percent Distribution – Top Coats 

Coating Category Percent Contribution for 

Group I Vehicles 

Percent Contribution for 

Group II Vehicles 

Multistage Coating 8.0 72.1 

Single Stage Coating 0.8 7.2 

Multi-Colored Coating 0.1 0.8 

Subtotal 8.9 80.1 

Total 89.0 
Staff Report for Proposed Amended Rule 1151 

FSR - 15 - December 2005 

Table 6 – Emissions Inventory Percent Distribution – Specialty Coatings 

Coating Category Percent Contribution for 

Group I Vehicles 

Percent Contribution for 

Group II Vehicles 

Adhesion Promoters 0.03 0.22 

Underbody Coating 0.01 0.07 

Uniform Finishing Coating 0.07 0.60 

Subtotal 0.11 0.89 

Total 1.0 

EMISSION REDUCTIONS

The emission reductions for the proposed amendments are estimated at 3.7 tpd and are presented 

in Table 7. The VOC emission reductions were calculated using a comparison of the current and 

proposed VOC emissions limits. Typically, this type of analysis is done on a solid basis. 

However, for this project, the replacement coatings are, in general, coatings that have the similar 

solid content by weight and specific gravity. The following provides the information and steps 

used to develop and calculate the data in Table 7. 

1. The total emissions inventory (7,519,000 lbs/yr) was distributed by categories using the 

information in tables 4, 5, and 6. 

2. The baseline usage of coatings (gallons per year), based on the current emissions inventory, 

was determined by dividing the emissions from each category by the current applicable VOC 

emission limit. This calculation yields the number of gallons currently used by each of the 

affected categories, assuming all coatings sold are at the current applicable limit. Although 

this estimate is a calculated number, the results generated correspond well to the data 

reported under the CARB 2002 Survey of Automotive Coatings. 

3. The usage for compliant coatings (gallons per year) is assumed to be equal to the estimated 

current usage since the solid content by weight, and specific gravity of both baseline and 

future coatings are assumed to be constant. This assumption is based on information 

provided by coating manufacturers. 

4. The ending emissions are then calculated by multiplying the proposed coating usage by the 

proposed emission limit. 

5. The emission reductions are calculated by using the difference of between current emissions 

and the ending emissions. 
Staff Report for Proposed Amended Rule 1151 

FSR - 16 - December 2005 

Table 7 – Emission Reductions 

Baseline Proposed Emission 

Reductions 

Coating 

Category 

Usage 

(gals/year) 

VOC 

Limit 

(lbs/gal) 

Emissions

(lbs/year) 

Usage 

(gals/year) 

VOC 

Limit 

(lbs/gal) 

Emissions 

(lbs/year) 

(lbs/year) (tons/day) 

Pretreatment 23,135 6.5 150,380 23,135 5.5 127,245 23,135 0.03 

Group II 

Primer 

Sealer 

61,763 2.8 172,937 61,763 2.1 129,703 43,234 0.06 

Single Stage 

(Group II) 

154,677 3.5 541,368 154,677 2.8 433,094 108,274 0.15 

Group I 

Multistage 

(Color 

Portion) 

143,219 4.2 601,520 143,219 3.5 501,267 100,253 0.14 

Group II 

Multistage 

(Color 

Portion) 

860,508 6.3 5,421,199 860,508 3.5 3,011,777 2,409,422 3.30 

Adhesion 

Promoter 

2,685 7.0 18,798 2,685 4.5 12,084 6,713 0.01 

Underbody 

Coating 

859 7.0 6,015 859 3.6 3,094 2,922 0.004 

Uniform 

Finishing 

Coating 

7,197 7.0 50,377 7,197 4.5 35,215 15,162 0.02 

Total 2,632,058 3.7 

COST AND COST-EFFECTIVENESS 

Although the proposed amendments to Rule 1151 are technology neutral, the cost and costeffectiveness analyses for PAR 1151 are based on a scenario that color coatings will transition 

from solvent borne to waterborne technology and that compliant coatings are or will be available 

in the market for the other coating categories that are affected by the proposal. Information 

provided by automobile coating manufacturers as part of the SCM public testimony as well as 

communication with AQMD staff indicate that coating manufacturers will rely on waterborne 

technology already available in Europe to comply with the proposed VOC limits. 

The cost and cost-effectiveness analyses for the proposed amendments to Rule 1151 have two 

main cost components: 1) the cost to coatings manufacturers to bring waterborne technology 

into the California market, and 2) the upgrade (to use waterborne technology) cost to refinishing 

facilities. No cost increases are assumed for the non-spray booth facilities since their operations 

will not change. These operations consist of the application of primers and single-stage coatings 

that comply with the current and future VOC limits. Cince there is no additional equipment 

required and the cost of the compliant coatings is not expected to change, there will be no 

additional cost to these operators. 
Staff Report for Proposed Amended Rule 1151 

FSR - 17 - December 2005 

The cost and cost-effectiveness analyses are based on the following assumptions that were 

developed in collaboration with CARB staff as part of the CARB SCM development work. 

1) The total cost to coating manufacturers to bring waterborne technology into the California 

market is approximately $14.4 million in non-reoccurring costs (CARB 2005). Assuming 

that the AQMD represents approximately 46 percent of the automotive refinish industry 

(based on population), the cost to manufacturers to supply waterborne coatings to the AQMD 

is estimated at $6,624,000. 

2) The capital costs for retrofit equipment at refinishing facilities is based on production (using 

total annual revenue as a surrogate), retrofit costs are capital investment costs for air 

movement equipment, heating equipment, replacement of mixing bank lids, upgrade of spray 

gun equipment, and the cost to upgrade waste disposal equipment. There are other nonreoccurring costs associate the change from solvent-borne to water-borne technology; these 

costs include employee training, material loss, and other incidental costs. All these costs and 

operational and maintenance costs are presented by facility size in Table 8. The cost 

presented in Table 8, were developed using the assumptions CARB staff used to estimate the 

cost of the CARB SCM. The per facility costs are the same used in the CARB SCM. 

However, the distribution of facilities is based on AQMD data using Dunn & Bradstreet data 

for the AQMD facilities. 

Table 8 – Capital, Non-Recurring, and O & M Estimates per Facility by Facility Size 

Facility 

Size/Description 

Non-Recurring 

Retrofit Equipment 

Costs 

Other Non-Recurring 

Costs 

O & M Costs 

(annual cost) 

Small 

One booth $3,100 $3,500 $155 

Small 

Two booths $4,700 $3,500 $235 

Medium 

Two booths no heating 

equipment $37,500 $4,500 $1,875 

Medium 

Two booths and existing 

heating equipment $11,500 $4,500 $575 

Large 

Two booths and existing 

heating equipment $41,500 $6,500 $2,075 

Large 

Three booths and 

existing heating 

equipment $61,500 $6,500 $3,075 
Staff Report for Proposed Amended Rule 1151 

FSR - 18 - December 2005 

3) There are 1,726 dedicated automotive refinishing facilities in the AQMD operating 

approximately 2,500 spray booths. 

4) 25 percent of the spray booths are heated-downdraft spray-booths. 

5) The facility distribution based on revenue, verified through Dunn & Bradstreet, are 78, 9, and 

13 percent small, medium, and large facilities, respectively. Small, medium, and large 

facilities are facilities with annual revenues of under $1,000,000, $1,000,000 to $2,500,000, 

and over $2,500,000, respectively. 

Based on these assumptions, the cost for the proposed amendments is presented in Table 9 – 

Cost Analysis. The costs are the product of the number of facilities in each category multiplied 

by the cost per facility presented in Table 7. 

Table 9 – Cost Analysis 

Facility 

Size/Description 

Facility Count Non-Recurring 

Retrofit 

Equipment Cost

Other 

Non-Recurring 

Cost 

Annual 

O & M 

Small 

w/ 1 booth 

1157 $3,586,700 $4,049,500 $179,335 

Small 

w/ 2 booths 

170 $799,000 $595,000 $39,950 

Medium 

w/ two booths no 

heating equipment 

84 $3,150,000 $378,000 $157,500 

Medium 

w/ 2 booths and 

existing heating 

equipment 

91 $1,046,500 $409,500 $52,325 

Large 

w/ two booths and 

existing heating 

equipment 

60 $2,490,000 $390,000 $124,500 

Large 

w/ two booths and 

existing heating 

equipment 

164 $10,086,000 $1,066,000 $504,300 

Totals 1726 $21,158,200 $6,888,000 $1,057,910 

The cost-effectiveness of the SCM was estimated by CARB staff using the levelized cash flow 

method of analysis. Consistent with the AQMD cost-effectiveness procedures, the discount cash 

flow method of analysis is used to calculate the cost-effectiveness for the proposed amendments 

to Rule 1151. The cost-effectiveness for the proposed amendments is calculated by the 

following equation. 

CE = [Capital Cost + (11.118 x Annual O& M)]/(Annual Emission Reductions x 15) 
Staff Report for Proposed Amended Rule 1151 

FSR - 19 - December 2005 

Where, 

 Capital Cost = Non-recurring costs to manufacturers + 

 Non-recurring equipment costs + non-recurring 

 other cost 

 11.118 = Present value factor for 15 years at 4% interest 

 15 = Assumed Productive Life of the Equipment in years 

The cost-effectiveness for the proposed amendments is: 

CE = [($6,624,000 + $21,158,200+$6,888,000) + ($1,057,910* 11.118)]/1351*15 

CE = ($34,670,200 + $11,761,843)/20,265 tons 

CE = $46,432,043/20,265 tons 

CE = $2,291 per ton of VOC Reduced 

INCREMENTAL COST-EFFECTIVENESS 

The incremental cost-effectiveness for Proposed Amended Rule 1151 is based on the affected 

facilities complying through the use of add-on controls. Specifically, this control option assumes 

that all spray booths operated by the automotive refinishing industry are controlled by addcontrols rather than the implementation of waterborne technology. The add-on control system 

assumed for this control option is a hybrid add-on control system that uses adsorption and 

catalytic incineration to achieve overall emission reductions of at least 85 percent. This type of 

system is considered Best Available Control Technology for integrated automotive downdraft 

spray booths. The capital and installation cost to equip one spray booth with such a system is 

estimated at $150,000.3

 There are approximately 2,500 spray booths operated by the refinishing 

industry in AQMD. Therefore, the total cost to equip all spray booths with add-on controls is 

estimated at 375 million dollars. The additional emission reductions are estimated by assuming 

90 percent capture efficiency and a 95 destruction efficiency across the control device or 85 

percent overall control efficiency. The alternative compliance option yields an emission 

reduction of 8.8 tpd. The compliance option proposed by AQMD staff yields an emission 

reduction of 3.7 tpd. Therefore, the additional emission reductions are estimated to be 5.1 tpd or 

1862 tons per year. 

Using the discounted cash flow method the annual cost of this control option assuming 15 years 

life for the equipment is calculated using the following equation: 

Annual Cost of Control Option = [Capital Cost + (11.118 x Annual O& M)]/15 

Where, 

 

3

 CAPCOA 2003 Engineering Symposium, April 1, 2003. 
Staff Report for Proposed Amended Rule 1151 

FSR - 20 - December 2005 

11.118 = Present value factor at 15 years and 4% interest 

Capital Cost for this control option= $375,000,000 

Annual O & M (Estimated to be 10%of Capital Cost) = $37,500,000 

Annual Cost of Control Option = [$375,000,000 + (11.118) 37,500,000)]/15 

 = $791,925,000/15 = $52,795,000 

The incremental cost-effectiveness is calculated by using the following equation: 

ICE = [Annual Cost of Control Option – Annual Cost of Proposal] 

/[Control Option Emission Reductions – Emissions reductions of the proposal]. 

ICE = [$ 52,795,000- $3,095,470]/[3,212 – 1,351 tons] 

ICE = $49,699,530/1,861 tons 

ICE = $26,706 per ton of additional VOC reduced. 

COMPARITIVE ANALYSIS 

As required by Health and Safety Code Section 40727.2, the purpose of this analysis is to 

identify and compare any other AQMD, or federal regulations that apply to the same equipment 

or source type. 40 CFR Part 9 and 59 – National Volatile Organic Compound Emissions 

Standards for Automotive Refinish Coatings (National Rule), sets VOC limits for some of the 

categories in Proposed Amended Rule 1151. These VOC limits are applicable to all coatings 

manufactured for use, or coatings imported for use in the United States. The categories and 

limits set by the national rule are presented in Table 10 – National Rule Categories and VOC 

Limits. The VOC limits of PAR 1151 are generally more stringent than those of the national 

rule, with the exception of multi-colored topcoats that is the same. 

Table 10 – National Rule Categories and VOC Limits 

Coating Category VOC Content Less Water and Exempts 

PAR 1151 (g/l) National Rule (g/l) 

Pretreatment Wash Primer 250 780 

Primer/Primer Surfacer 250 580 

Primer Sealer 250 550 

Single/2-stage Topcoats 340/250-420 600 

Topcoats of 3 or more stages 250-420 630 

Multi-Colored topcoats 680 680 

Specialty Coatings 60-660 840 

DRAFT FINDINGS
Staff Report for Proposed Amended Rule 1151 

FSR - 21 - December 2005 

Before adopting, amending or repealing a rule, the AQMD shall make findings of necessity, 

authority, clarity, consistency, non-duplication, and reference, as defined in Health and Safety 

Code Section 40727. The draft findings are as follows: 

Necessity - The AQMD Governing Board finds and determines that Proposed Amended Rule 

1151 – Motor Vehicle and Mobile Equipment Non-Assembly Line Coating Operations, is 

necessary in order to implement the 2003 Ozone Air Quality Management Plan and to achieve 

the VOC emission reduction targets. 

Authority - The AQMD Governing Board obtains its authority to adopt, amend or repeal rules 

and regulations from Health and Safety Code §§40000, 40001, and 40440. 

Clarity - The AQMD Governing Board finds and determines that Proposed Amended Rule 1151 

– Motor Vehicle and Mobile Equipment Non-Assembly Line Coating Operations, is written and 

displayed so that the meaning can be easily understood by persons directly affected by it. 

Consistency – The AQMD Governing Board finds and determines that Proposed Amended Rule 

1151 – Motor Vehicle and Mobile Equipment Non-Assembly Line Coating Operations, is in 

harmony with, and not in conflict with or contradictory to, existing statutes, court decisions, or 

federal or state regulations. 

Non-Duplication – The AQMD Governing Board has determined that Proposed Amended Rule 

1151 – Motor Vehicle and Mobile Equipment Non-Assembly Line Coating Operations, does not 

impose the same requirements as any existing state or federal regulations. 

Reference - In adopting these proposed amendments, the AQMD Governing Board references 

the following statutes which AQMD hereby implements, interprets or makes specific: Health and 

Safety Code Sections 40001 and 40440. 

PUBLIC COMMENTS AND RESPONSES 

Comment 1: The District should not exempt TBAc as part of the proposed amendments to Rule 

1151. The appropriate rule to consider the exemption of TBAc as a VOC is Rule 

102. However, the commenter opposes a full or limited exemption of TBAc as a 

VOC on the basis that there is little toxicity information on TBAc. Currently, the 

exemption of TBAc can only be evaluated using an inhalation unit risk value for 

tert-butyl alcohol (TBA) which is a metabolic product of TBAc. There is limited 

toxicity data available for TBAc itself and the chemical has not been tested for 

chronic toxicity. If TBAc were a carcinogen and was a more potent carcinogen 

than TBA, the risk calculated for TBAc would be underestimated. 

Response 1: The exemption of TBAc as a VOC for automotive refinishing is being addressed 

within the amendments to Rule 1151 and not in Rule 102 consistent with the 

recommendations made by Cal/EPA as part of their environmental document to 

exempt TBAc from the VOC definition in the CARB Consumer Products 

Regulation. 
Staff Report for Proposed Amended Rule 1151 

FSR - 22 - December 2005 

 At this point, AQMD staff has decided to examine the impacts of TBAc as a VOC 

to be evaluated specifically for this industry opposed to a complete exemption 

under Rule 102. 

 CARB evaluated the exemption of TBAc as a VOC in their SCM. Based on their 

analysis the maximum carcinogenic risk was estimated at 2.8 in one million. 

AQMD staff evaluated the potential carcinogenic risk based on a more 

conservative analysis for the TBAc exemption by including the possible 

replacement of other exempt compounds namely PCBTF and acetone. This 

assessment was part of the CEQA analysis for PAR 1151 and is included in the 

Draft Environmental Assessment (EA). Based on AQMD risk assessment 

analysis and public comments, staff has concluded that the exemption should be 

limited to Rule 1151 coating categories other than the color and clear coating 

categories. The limited exemption using a worst case analysis (that includes the 

100 percent replacement of PCBTF and acetone with TBAc) estimated a 

carcinogenic risk of five in one million for 13 facilities subject to PAR 1151. 

However, it is important to note that of the remaining facilities, 105 would have a 

risk between one and less than five in one million, and 1,609 would have a risk of 

less than one in one million. Additionally, the results of the worst case 

carcinogenic risk analysis are below the CEQA threshold of 10 in one million. 

Furthermore, staff is also proposing to conduct a technical analysis regarding the 

toxicity or potential toxicity of TBAc. This commitment is included in the 

proposed rule language and will also be included in the Adopting Board 

Resolution. 

Comment 2: The AQMD should conduct additional studies to ensure that TBAc is not a health 

risk if it is exempted as a VOC in the proposed amendments to Rule 1151. 

Response 2: In considering the exemption for TBAc AQMD staff conducted a risk analysis as 

part of the CEQA analysis and included it in the Draft EA (see response to 

comment 2) and has evaluated the public comments on the issue. Based on this 

analysis and public comments received that included the benefits of TBAc in the 

reduction of ground level ozone, staff has concluded that a limited exemption for 

TBAc as a VOC is appropriate. 

Comment 3: TBAc and its metabolic product TBA have not been found to be a carcinogen by 

any national or international public health research organization. TBAc has been 

exempted as a VOC by U.S.EPA and CARB has recommended the AQMD to 

exercise caution when exempting TBAc as a VOC. TBAc would provide health 

benefits by replacing known toxic air contaminants in automotive refinishing 

coatings including toluene, xylene, and MEK. The CARB TBAc environmental 

impact analysis states that the benefits from ozone reduction outweigh any 
Staff Report for Proposed Amended Rule 1151 

FSR - 23 - December 2005 

perceived toxic effects of TBAc. On this basis, we request the AQMD issue a 

complete exemption of TABC as a VOC. 

Response 3: As stated in response to comment 1, staff has evaluated the exemption of TBAc 

and has concluded based on the results of health risk analysis and public 

testimony that a limited exemption for TBAc would effectively minimize the 

potential health risk while providing some flexibility in formulating compliant 

products. To this end, staff is proposing to exempt TBAc as a VOC only for Rule 

1151 coating categories, other than the color and clear coating categories. 

Comment 4: The majority of the emission reductions benefits from the proposed amendments 

to Rule 1151 are generated from the reduction on the VOC limit for the color 

coating category. Currently, there are no compliant coatings available to meet the 

proposed limits for primer sealer, adhesion promoters, and single stage coatings 

for Group II type vehicles. We request that the AQMD maintain the current VOC 

limits for these three coating categories. The impact in terms of VOC emission 

reductions to the proposed project is minimal. 

Response 4: According to information provided to CARB and AQMD staff, there are epoxy, 

isocyanate-free, and polyurethane two-component primer sealers for automotive 

refinishing (Group II quality) currently available in the market that meet the 

proposed VOC limit of 2.1 pounds per gallon. Relative to the adhesion 

promoters, CARB has received information from coating manufacturers 

indicating that compliant products would soon be available in the market place. 

The effective compliance date of January 1, 2009 allows the time necessary for 

completion of the development of compliant coatings and their implementation in 

the market place. 

Comment 5: There are products available in the markets that meet the proposed limits for the 

primer (primer sealer for passenger vehicles) and the single stage coating 

categories. 

Response 5: Thank you, your comment has been noted. 

Comment 6 : Please specify the specific conditions for compliance with the prohibition of 

possession. 

Response 6: Effective July 1, 2006, a person can be in possession of non-compliant coatings

only if the coating is located at a facility that an emission control device and those 

coatings meet the limits specified in the permit conditions of the coatings at the 

facility or the coating is located at a facility that operates in compliance with an 

approved alternative compliance plan or the coatings are needed at an exempt 
Staff Report for Proposed Amended Rule 1151 

FSR - 24 - December 2005 

coating training center or exempted prototype motor vehicle manufacturing 

facility. 

Comment 7: The future proposed VOC limits will cause manufacturers to change the 

chemistries of current automotive coatings. The new compliant coatings will 

most likely require changes to the methods and techniques of how the automotive 

coating “shops” effectively apply these new coatings. Automotive coating 

applicators will need some time to familiarize themselves with these new coating 

technologies prior to the proposed effective date of January 1, 2009. Please 

consider phasing-in the proposed future limits for the different categories rather 

than having them effective at the same time. 

Response 7: Staff has revised the proposed amendments to phase in the proposed VOC limits 

for color and clear coatings effective on July 1, 2008. At the same time, staff has 

included a sell-through provision that allows the sale, possession and use of noncompliant color and clear coatings until December 31, 2008. This revision will 

provide coating applicators six months to familiarize themselves with the new 

color and clear coating technologies. All other VOC limits will be effective 

January 1, 2009. The proposed amendments to Rule 1151 are comparable to the 

CARB SCM that has an implementation date of January 1, 2009, with no sell 

through provision for these categories. 

Comment 8: As it relates to the existing version of Rule 1151, please clarify whether sport 

utility vehicles (SUVs) that have a manufacturer’s gross vehicle weight greater 

than 8,600 pounds are Group I Vehicles or Group II Vehicles. 

Response 8: At the time Rule 1151 was last amended there were no SUVs that had a 

manufacturer’s gross vehicle weight of greater than 8,600 pounds. A SUV, 

regardless of the gross weight, is designed primarily to transport less than twelve 

passengers and clearly fits the definition of passenger car. Although, there is 

overlap with the definition of bus and large truck based on the 8,600 pound gross 

vehicle weight for some SUVs, the function of an SUV more closely fits the 

definition of passenger car and for the purpose of Rule 1151 all SUVs are 

classified as Group II Vehicles. 

Comment 9: The compliance date for adhesion promoters, primers, and single-stage coatings 

was delayed to January 1, 2010 as part of the adoption by CARB of the SCM for 

Automotive Coatings on October 20, 2005. Please be consistent with the SCM 

and delay the implementation date for adhesion promoters, primer, and singlestage coatings to January 1, 2010. 

Response 9: The implementation date for the adhesion promoters, primers and single-stage 

coating categories has been moved from January 1, 2009 to January 1, 2010. 
Staff Report for Proposed Amended Rule 1151 

FSR - 25 - December 2005 

Comment 10: Please be aware that there are UV-technology based compliant coatings available 

to meet the proposed VOC limits. Please include this information in the staff 

report. 

Response 10: Staff agrees that UV coatings may be available that can and will meet the current 

and future VOC limits in PAR 1151. PAR 1151 is technology neutral and any 

coating that complies with the VOC limits specified in the rule may be used. 
Staff Report for Proposed Amended Rule 1151 

FSR - 26 - December 2005 

REFERENCES 

1. Final Staff Report for: Proposed Amended Rule 1151 – Motor Vehicle and Mobile 

Equipment Non-Assembly Line Coating Operations, August 6, 1991. 

2. Staff Report for the Proposed Suggested Control Measure for Automotive Coatings, 

California Environmental Protection Agency, Air Resources Board, Stationary Source 

Division, Measures Assessment Branch, October 2005. 

3. Directive 2004/42/CE of the European Parliament and of the council, April 2004 

4. European Commission Reducing VOC Emissions from the Vehicle Refinishing Sector, Entec 

UK Limited and The Paint Research Association, August 2000. 

5. 40 CFR Part 51, Revision of Volatile Organic Compounds - Exclusion of t-butyl Acetate, 

USAEPA, December 2004. 

6. EnviroCure Abatement Systems, CAPCOA 2003 Engineering Symposium, April 2003. 

7. 40 CFR Parts 9 and 59 – National Volatile Organic Compound Emission Standards for 

Automobile Refinishing Coatings. 

8. Environmental Impact Assessment of Tertiary-Butyl Acetate (Draft) Staff Report, Cal/EPA 

CARB June 2005