### 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 applic ation 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 protec t public health with an ample margin of safety or to prevent (taking into consideratio n various factors) advers e 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 Nationa l 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 asse ssments 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 r easonable since they reflect the

1

### 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 perf orm 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 coatin gs (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 assessm ent 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 ma terial type. This method is known as using compliant coatings. While wood furniture faci lities 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 comply ing 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 usag e coating categories and found the reported VHAP contents were generally 50 to 100 percent of the applicable VHAP limit, de pending on the specific types of coatings used.

Table 2 summarizes several examples of repr esentative coatings with the VHAP contents and the applicable NESHAP coating limit. (The re 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 hi gh as two times (2X) the actual emissions from wood furniture operations.

2

### 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); 1.0 a 0.8 a

(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 1.0 a 1.0 a b

1.0 a 1.0 a 1.0 a b
1.0 a b
10.0 1.0 a 0.8 a b

0.8 a 0.8 a 0.8 a b
0.8 a b
10.0

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

(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 NA d NA d

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 1.0 e 0.2 e

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 ta ble 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 fo rmulated using compliant finishing ma terials, 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.

34 

### 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 comp any website (http://www.chemcraft.com) on 9/2/10

.