UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: April 5, 2016

SUBJECT: Technical Support Document – Control of Volatile Organic Compound Emissions 

from Fiberglass Boat Manufacturing Materials 

/s/

FROM: Irene Shandruk, Physical Scientist 

Office of Air Program Planning 

TO: File

/s/

THRU: Cristina Fernandez, Associate Director 

Office of Air Program Planning

A. BACKGROUND 

Section 172(c)(1) of the Clean Air Act (CAA) 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 

sources of volatile organic compound (VOC) emissions covered by a control techniques 

guidelines (CTG) document issued after November 15, 1990 and prior to the area’s 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. 

CTGs are intended to provide state and local air pollution control authorities information that 

should assist them in determining RACT for VOCs from various sources fiberglass boat 

manufacturing materials. In developing CTGs, EPA, among other things, evaluated the sources 

of VOC emissions from this 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 VOCs from various industry categories, including

fiberglass boat manufacturing.
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EPA has not published a previous CTG for fiberglass boat manufacturing materials, but did 

publish an assessment of VOC emissions from fiberglass boat manufacturing in 1990. The 1990 

assessment defined the nature and scope of VOC emissions from fiberglass boat manufacturing, 

characterized the industry, estimated per plant and national VOC emissions, and identified and 

evaluated potential control options. In 2001, EPA promulgated the National Emission Standards 

for Hazardous Air Pollutants for Boat Manufacturing, 40 CFR part 63, subpart VVVV (2001 

NESHAP). The 2001 NESHAP established organic hazardous air pollutant (HAP) emissions 

limits based on low-HAP resins and gel coats and low-emitting resin application technology. 

Several of the air pollution control districts in California have specific regulations that control 

VOC emissions from fiberglass boat manufacturing operations, as part of their regulations for 

limiting VOC emissions from polyester resin operations. Several other states also have 

regulations that address VOC emissions from fiberglass boat manufacturing as part of polyester 

resin operations. After reviewing the 1990 VOC assessment, the 2001 NESHAP, and existing 

California district and other State VOC emission reduction approaches, and after considering 

information obtained since the issuance of the 2001 NESHAP, EPA developed a CTG entitled

Control Techniques Guidelines for Fiberglass Boat Manufacturing Materials (Publication No. 

EPA 453/R-08-004; September 2008).

Description of Fiberglass Boat Manufacturing Materials

The CTG for fiberglass boat manufacturing materials provides control recommendations for 

reducing VOC emissions from the use of gel coats, resins, and materials used to clean

application equipment in fiberglass boat manufacturing operations. This CTG applies to 

facilities that manufacture hulls or decks of boats from fiberglass, or build molds to make 

fiberglass boat hulls or decks (hereinafter referred to as “fiberglass boat manufacturing 

facilities”). Recommendations in this CTG do not extend to facilities that manufacture solely 

parts of boats (such as hatches, seats, or lockers), or boat trailers, but do not manufacture hulls or 

decks of boats from fiberglass, or build molds to make fiberglass boat hulls or decks. If a facility 

manufactures hulls or decks, or molds for hulls or decks, then the manufacture of all other 

fiberglass boat parts, including small parts such as hatches, seats, and lockers is also covered. 

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

fiberglass boat manufacturing facility where the total actual VOC emissions from all fiberglass 

boat manufacturing operations covered by the recommendations in section VI of this CTG are 

equal to or exceed 6.8 kg/day (15 lb/day). An alternative equivalent threshold would be 2.7 tons 

per 12-month rolling period. Cleaning materials should be included in determining whether total 

actual VOC emissions exceed this level. If a facility has add-on controls, then emissions before 

the add-on controls should be used in determining if a facility meets this threshold.

EPA’s Recommended Control Options for Fiberglass Boat Manufacturing Materials

EPA’s 2008 CTG recommends that the following operations are covered:

• Open molding resin and gel coat operations (these include pigmented gel coat,

 clear gel coat, production resin, tooling gel coat, and tooling resin);

• Resin and gel coat mixing operations; and

• Resin and gel coat application equipment cleaning operations.
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EPA’s 2008 CTG recommends the following VOC reduction measures: VOC emission limits 

for molding resins and gel coats; work practices for resin and gel coat mixing containers; and 

VOC content and vapor pressure limits for cleaning materials. Recommended VOC emission 

limits for open molding resin and gel coat operations are shown in Table 1.

Table 1: Monomer VOC Content Limitations for Open Molding Resin and Gel Coat Operations

Materials Application Method Individual Monomer VOC 

Content or Weight Average 

Monomer VOC Content Limit 

(weight percent)

Production Resin Atomized (spray) 28

Production Resin Nonatomized 35

Pigmented Gel Coat Any Method 33

Clear Gel Coat Any Method 48

Tooling Resin Atomized 30

Tooling Resin Nonatomized 39

Tooling Gel Coat Any Method 40

Alternatively, the applicable recommended limits in Table 1 above would be considered met if 

all materials of a certain type meet the applicable monomer VOC content limit for a specific 

application method on a weighted-average basis, and each resin and gel coat did not contain 

more than 5 percent non-monomer VOC. The weighted-average monomer VOC content would 

be determined based on a 12-month rolling average. A facility would use Equation 1 found on 

p. 27 of Control Techniques Guidelines for Fiberglass Boat Manufacturing Materials

(Publication No. EPA 453/R-08-004; September 2008) to determine weighted-average monomer 

VOC content for a particular open molding resin or gel coat material.

Under the emissions averaging option, monomer VOC emissions from the open molding resin 

and gel coat operations that a facility chooses to include in this emission average option would

meet a facility-specific monomer VOC mass emission limit (12-month rolling average) that is 

determined using Equation 2 found on p. 28 of Control Techniques Guidelines for Fiberglass 

Boat Manufacturing Materials (Publication No. EPA 453/R-08-004; September 2008). All 

resins and gel coats included in this option would also need to meet the recommended nonmonomer VOC content limit of 5 percent.

The CTG recommends that the emissions average be calculated on a 12-month rolling average

basis and determined at the end of every month (12 times per year). It further recommends that 

at the end of the first 12-month averaging period and at the end of every subsequent month, a 

facility use Equation 3 found on p. 29 of Control Techniques Guidelines for Fiberglass Boat 

Manufacturing Materials (Publication No. EPA 453/R-08-004; September 2008) to show that the 

monomer VOC emissions from the operations included in the average do not exceed the

emission limit calculated using Equation 2 for the same 12-month period.

The formulas in Table 4 found on p. 30 of Control Techniques Guidelines for Fiberglass Boat 

Manufacturing Materials (Publication No. EPA 453/R-08-004; September 2008) calculate 

monomer VOC emission rates in kilograms of monomer VOC per megagram of resin or gel coat 

applied. The formulas for vacuum bagging with roll-out are applicable when a facility rolls out 
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the applied resin and fabric prior to applying the vacuum bagging materials. The formulas for 

vacuum bagging without roll-out are applicable when a facility applies the vacuum bagging 

materials immediately after resin application without rolling out the resin and fabric. VOC% =

monomer VOC content as supplied, expressed as a weight-percent value between 0 and 100 

percent.

If product performance requirements or other needs dictate the use of higher monomer

VOC materials than those that would meet the recommended emission limits in Table 1, a 

facility could choose to use add-on control equipment to meet the emission limit. However, 

instead of using the mass of each material used over the past 12 months in Equation 2, the 

facility would use the mass of each material used during the control device performance test in 

Equation 2 to determine the emission limit (in kg of monomer VOC) that is applicable during the 

test. If the measured emissions at the outlet of the control device (in kg of monomer VOC) are 

less than the emission limit, then the facility would be considered to have achieved the emission 

limit.

Some facilities use resins to which fillers are added to achieve certain physical properties, 

particularly for building molds. The resins to which the filler is added have higher initial 

monomer VOC content than standard production or tooling resins, but the addition of the filler 

lowers the monomer VOC emission rate from the filled resin. The CTG recommends the use of 

Equation 5 found on p. 32 of Control Techniques Guidelines for Fiberglass Boat Manufacturing 

Materials (Publication No. EPA 453/R-08-004; September 2008) to adjust the emission rate for 

filled resins under all three options recommended above for limiting monomer VOC emissions 

from resins and gel coats. If a facility is using a filled production resin or filled tooling resin, it

would calculate the emission rate for the filled material on an as-applied basis using Equation 5.

B. STATE SUBMITTAL

On March 2, 2016, Pennsylvania Department of Environmental Protection (PADEP) submitted 

to EPA a SIP revision concerning implementation of RACT requirements for the control of VOC 

emissions from fiberglass boat manufacturing materials. EPA develops CTGs as guidance on 

control requirements for source categories. States can follow the CTGs or adopt more restrictive 

standards. Pennsylvania is adopting EPA’s CTG standards for fiberglass boat manufacturing 

materials, including the emission limits found in Table 1 as well as all alternative options for 

calculating emissions discussed earlier in this Technical Support Document as well as in the 

CTG itself. The regulation is contained in 25 Pa. Code Chapter 129 (relating to standards for 

sources), and this SIP revision adds section 129.74 (control of VOC emissions from fiberglass 

boat manufacturing materials) to the Pennsylvania SIP. In addition to adopting the CTG

standards discussed above, section 129.74 includes numerous terms and definitions to support 

the interpretation of the measures, as well as work practices for cleaning; compliance and 

monitoring requirements; sampling and testing; and record keeping requirements (all included in 

section 129.74 of the Pa. Code)

This SIP revision also notes that the requirements of section 129.74 supersede the requirements 

of a RACT permit issued under sections 129.91-129.95 prior to December 19, 2015 to the owner 

or operator of a source subject to section 129.74 to control, reduce, or minimize VOCs from a 
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fiberglass boat manufacturing process, except to the extent the RACT permit contains more 

stringent requirements. 

C. EPA EVALUATION AND RECOMMENDED AGENCY ACTION

Pennsylvania has adopted all of the standards and requirements of the fiberglass boat 

manufacturing materials CTG and is revising the Pennsylvania SIP to reflect this addition. Thus, 

the SIP revision is approvable pursuant to sections 172(c)(1) and 182(b)(2) of the CAA. The SIP 

revision will reduce emissions of VOCs from fiberglass boat manufacturing operations. The 

maximum benefit from this addition will be provided during the ozone season when VOCs 

readily combine with NOx to form ground-level ozone. Therefore, this revision will help 

Pennsylvania attain and maintain the NAAQS for ozone. EPA approval of the SIP revision is 

recommended.