September 9, 2010 

MEMORANDUM

TO: Dave Guinnup, Leader 

 Sector Based Assessment Group 

FROM: Kaye Whitfield, Project Lead 

Risk and Technology Review - National Emission Standards for Hazardous Air 

Pollutants (NESHAP) for Wood Furniture Manufacturing 

SUBJECT: Maximum Achievable Control Technology (MACT) Allowable Emission 

Estimates 

Section 112(f)(2) of the Clean Air Act (CAA) directs EPA to assess the risk remaining 

(residual risk) after the application of maximum achievable control technology (MACT) 

standards under section 112(d). EPA is to promulgate more stringent standards for a category or 

subcategory of sources subject to MACT standards under section 112(d) if promulgation of such 

standards is necessary to protect public health with an ample margin of safety or to prevent 

(taking into consideration various factors) adverse environmental effects. 

In an effort to streamline the process of making residual risk decisions, EPA plans to 

address residual risk and perform a technology review simultaneously for the wood furniture 

manufacturing source category. The first part of this approach is to compile and review (and 

update with facility-specific data collected by EPA in some cases) readily available source 

category emissions data from the 2005 National Emissions Inventory (NEI), to conduct 

preliminary risk assessments, and to make the data and results available for public review. 

For the most part, the emissions values from the NEI represent actual emission levels for 

wood furniture surface coating operations. The use of actual emissions versus the use of 

“MACT allowable” emissions for residual risk assessments was discussed both in the final Coke 

Oven Batteries residual risk rule (70 FR 19998-19999, April 15, 2005) and in the proposed and 

final Hazardous Organic National emission standard for hazardous air pollutants (HON) residual 

risk rules (71 FR 34428, June 14, 2006, and 71 FR 76609, December 21, 2006, respectively). In 

those previous actions, EPA noted that assessing the MACT allowable levels of emissions (i.e., 

the highest emission levels that could be emitted while maintaining the same activity level and 

still complying with the NESHAP requirements) is inherently reasonable since they reflect the 

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maximum level sources could emit and still comply with national emission standards. It is 

reasonable to consider actual emissions, where such data are available, in both steps of the risk 

analysis, in accordance with the Benzene NESHAP. (54 FR 38044, September 14, 1989). 

Sources typically seek to perform better than required by emission standards to allow for 

variability in manufacturing processes and control device performance. 

For the wood furniture source category, the MACT standards are in the format of volatile 

organic HAP (VHAP) limits for several different types of surface coatings (see Table 1 below 

for a summary of the wood furniture coating VHAP limits from the wood furniture NESHAP) 

and work practice standards that minimize evaporative emissions and spills from the handling, 

transfer, and storage of organic thinning solvent and paint wastes. 

The most prudent approach to a risk assessment of the wood furniture industry is to 

consider both the actual emissions and the “MACT allowable” emissions. To meet the 

requirements of the NESHAP, facilities have an option of using only coatings and thinners that 

meet the individual HAP content requirements by material type. This method is known as using 

compliant coatings. While wood furniture facilities are also allowed to average the VHAP 

content across all coatings or to use add-on control devices to determine compliance, using 

compliant coatings is a simpler method of complying with the NESHAP. The coatings typically 

have lower HAP content than required by the NESHAP to allow for operational and market 

variability. 

We conducted an assessment of the actual emissions-to-MACT allowable emissions 

relationship for the highest usage coating categories and found the reported VHAP contents were 

generally 50 to 100 percent of the applicable VHAP limit, depending on the specific types of 

coatings used. 

 Table 2 summarizes several examples of representative coatings with the VHAP contents 

and the applicable NESHAP coating limit. (There are several wood furniture coating suppliers 

and hundreds of different coatings used at wood furniture facilities and the listed coatings are 

only intended as examples of high usage coatings.) Based on this available information, we 

estimate MACT allowable emissions to be as high as two times (2X) the actual emissions from 

wood furniture operations. 

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Table 1: Summary of Emissions Limits

Emission point Existing source New source 

Finishing Operations

(a)Achieve a weighted average VHAP content across all coatings 

(maximum kg VHAP/kg solids [lb VHAP/lb solids], as applied); 

1.0a 0.8a

(b)Use compliant finishing materials (maximum kg VHAP/kg solids [lb 

VHAP/lb solids], as applied); 

 - stains 

 - washcoats 

 - sealers 

 - topcoats 

 - basecoats 

 - enamels 

 - thinners (maximum % HAP allowable); or 

1.0a

1.0a b

1.0a

1.0a

1.0a b

1.0a b

10.0 

1.0a

0.8a b

0.8a

0.8a

0.8a b

0.8a b

10.0

(c)As an alternative, use control device; or 1.0c 0.8c

(d)Use any combination of (a),(b), and (c) 1.0 0.8

Cleaning Operations

Strippable spray booth material (maximum VOC content, kg VOC/kg solids 

[lb VOC/lb solids]) 

0.8 0.8

Contact Adhesives

(a)Use compliant contact adhesives (maximum kg VHAP/kg solids [lb 

VHAP/lb solids], as applied) based on following criteria 

 i.For aerosol adhesives, and for contact adhesives applied to nonporous 

substrates 

NAd NAd

 ii.For foam adhesives used in products that meet flammability requirements 1.8 0.2

 iii.For all other contact adhesives (including foam adhesives used in 

products that do not meet flammability requirements); or 

1.0 0.2

(b)Use a control device 1.0e 0.2e

a

 The limits refer to the VHAP content of the coating, as applied. 

b Washcoats, basecoats, and enamels must comply with the limits presented in this table if they are purchased 

premade, that is, if they are not formulated onsite by thinning other finishing materials. If they are 

formulated onsite, they must be formulated using compliant finishing materials, i.e., those that meet the 

limits specified in this table, and thinners containing no more than 3.0 percent HAP by weight. c The control device must operate at an efficiency that is equivalent to no greater than 1.0 kilogram (or 

0.8 kilogram) of VHAP being emitted from the affected emission source per kilogram of solids used. 

d There is no limit on the VHAP content of these adhesives. 

e The control device must operate at an efficiency that is equivalent to no greater than 1.0 kilogram (or 

0.2 kilogram) of VHAP being emitted from the affected emission source per kilogram of solids used. 

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Table 2 – Examples of wood furniture coatings 

Coating Coating 

Category 

VHAP* 

Content 

 (lb/lb solids) 

NESHAP 

Limit 

(lb/lb solids) 

% of Allowable 

MACT Limit 

Ratio of 

MACT 

Allowable to 

Actual 

Compliant 

Acrilico 

Sealer 

sealer 0.50 1.0 50% 2.00 

ora Verde® 

Chiaro PU 

Topcoat 

topcoat 0.68 1.0 68% 1.47 

Verde ora 

Verde® 

Chiaro PU 

Sealer 

sealer 0.68 1.0 68% 1.47 

Chemcraft 

Danseal sealer <0.70 1.0 70% 1.43 

Chemcraft 

Chemlack 

White Topcoat 

topcoat <0.78 1.0 78% 1.28 

Chemcraft 

Chembase II primer <0.80 1.0 80% 1.25 

Valspar 

VALTHANE 

Self-Seal 

Urethane 

Topcoats 

topcoat <0.80 1.0 80% 1.25 

Chemguard II coating 1.0 1.0 100% 1.00 

*Based on product data sheets downloaded from company website (http://www.chemcraft.com) on 9/2/10 

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