MEMORANDUM

TO: Kim Teal, U.S. EPA/OAQPS 

FROM: Eastern Research Group, Inc. 

DATE: October 29, 2015 

SUBJECT: Technology Review for Waste Storage and Handling Operations in the Aerospace 

Manufacturing and Rework Source Category 

1.0 INTRODUCTION

Section 112 of the Clean Air Act (CAA) requires the U.S. Environmental Protection 

Agency (EPA) to establish technology-based standards for listed source categories. These 

technology-based standards are often referred to as maximum achievable control technology 

(MACT) standards. The Aerospace MACT (40 CFR part 63, subpart GG) regulates HAP 

emissions from facilities that are major sources and are engaged, either in part or in whole, in the 

manufacture or rework of commercial, civil, or military aerospace vehicles or components. The 

rule requires the use of MACT to reduce HAP emissions from the following operations: 

cleaning; primer, topcoat and chemical milling maskant application; depainting; and waste 

storage and handling. 

Section 112 also contains provisions requiring the EPA to periodically revisit these 

standards. Specifically, section 112(d)(6) states: 

(6) REVIEW AND REVISION. – The Administrator shall review, and revise as 

necessary (taking into account developments in practices, processes, and control 

technologies), emissions standards promulgated under this section no less often than 

every 8 years. 

To comply with this CAA requirement, the EPA conducted a technology review for the 

Aerospace MACT standard for major sources. This memorandum addresses the portion of the 

technology review for waste storage and handling from the aerospace manufacturing and rework 

surface coating operations. 

For the purposes of reviewing a MACT standard, the EPA considers a “development” in 

practices, processes, and control technologies to be: 

• Any add-on control technology or other equipment that was not identified and considered 

during MACT development; 

www.erg.com 
• Any improvements in add-on control technology or other equipment (that was identified 

and considered during MACT development) that could result in significant additional 

emission reduction; 

• Any work practice or operational procedure that was not identified and considered during 

MACT development; and 

• Any process change or pollution prevention alternative that could be broadly applied that 

was not identified and considered during MACT development. 

• Any significant changes in the cost (including cost effectiveness) of applying controls 

(including controls the EPA considered during the development of the original MACT 

standards). 

Section 2 of this memorandum presents a summary of the sources of data that were used 

to conduct the technology review, and Section 3 presents the technology review for waste 

storage and handling. 

2.0 SOURCES OF AVAILABLE CONTROL TECHNOLOGY INFORMATION 

To identify any developments in practices, processes, or control technologies that could 

be applicable to waste storage and handling operations in the Aerospace industry, we consulted 

the following sources of data: RACT/BACT/LAER Clearinghouse, the California Statewide Best 

Available Control Technology (BACT) Clearinghouse, regulatory actions promulgated 

subsequent to the Aerospace MACT, and regional and state regulations. 

The EPA did not find any information specific to waste storage and handling for surface 

coating operations in the California BACT Clearinghouse. 

In addition, the EPA sent out a comprehensive information collection request (ICR) to all 

known aerospace manufacturing and rework facilities in February 2011. The ICR requested 

information on material usage and control techniques used on all of the regulated and 

unregulated emission sources. The 2011 ICR did not request information specific to waste 

storage and handling operations, although it did request information on cleaning operations and 

on storage tanks associated with regulated operations. However, the information was not 

sufficiently detailed to identify waste storage and handling operations that were not part of the 

cleaning operations, or that were part of the surface coating operations and not subject to another 

NESHAP. 

2.1 RACT/BACT/LAER Clearinghouse Database 

Under the EPA's New Source Review (NSR) program, if a company is planning to build 

a new plant or modify an existing plant such that criteria air pollution emissions will increase by 

a certain amount, then the company must obtain an NSR permit. The NSR permit is a 

construction permit which generally requires the company to minimize air pollution emissions by 

changing the process to prevent air pollution and/or installing air pollution control equipment. 

The terms "RACT," "BACT," and "LAER" are acronyms for different program 

requirements relevant to the NSR program. RACT, or Reasonably Available Control 

Technology, is required on sources in areas that are not meeting national ambient air quality 
standards (non-attainment areas). BACT, or Best Available Control Technology, is required on 

new or modified major sources in clean areas (attainment areas). LAER, or Lowest Achievable 

Emission Rate, is required on new or modified major sources in non-attainment areas. 

BACT and LAER (and sometimes RACT) are determined on a case-by-case basis, 

usually by state or local permitting agencies. The EPA established the RACT/BACT/LAER 

Clearinghouse, or RBLC, to provide a central data base of air pollution technology information 

(including past BACT and LAER decisions contained in NSR permits) to promote the sharing of 

information among permitting agencies and to aid in future case-by-case determinations. 

However, data in the RBLC are not limited to sources subject to RACT, BACT, and LAER 

requirements. Noteworthy prevention and control technology decisions and information may be 

included even if they are not related to past RACT, BACT, or LAER decisions.1 

The RBLC contains over 5,000 air pollution control permit determinations that can help 

identify appropriate technologies to mitigate most air pollutant emission streams. It was designed 

to help permit applicants and reviewers make pollution prevention and control technology 

decisions for stationary air pollution sources, and includes data submitted by several U.S. 

territories and all 50 States on over 200 different air pollutants and 1,000 industrial processes. 

The RBLC provides several options for searching the permit database on-line to locate 

applicable control technologies. On September 26 and 27 and October 25, 2013, we conducted a 

search of the RBLC. There is no process category in the RBLC that closely matches waste 

storage and handling. Our search specified processes in the Waste Disposal category, Other 

Waste Processing and Disposal subcategory, with permits dating back to September 1, 1995, 

which is the promulgation date of the Aerospace MACT. The searches of these process 

categories returned no determinations for processes that were at all similar to the waste storage 

and handling affected source at aerospace facilities. 

We also searched the RBLC for the Aerospace Surface Coating process category and 

other similar surface coating processes (Automobiles and Trucks Surface Coating (OEM), Large 

Appliance Surface Coating, Miscellaneous Metal Parts and Products Surface Coating, and Plastic 

Parts and Products Surface Coating) and other process categories that would be expected to 

generate waste solvents (Organic Solvent Cleaning and Degreasing, Halogenated Solvent 

Cleaning). We found no entries related to the waste storage and handling affected facility as 

defined in the aerospace standard. Finally, we searched the RBLC across all process categories 

for any that contain the word “waste.” While there are many such entries, none were related to 

the waste storage and handling affected source; most were related to wastewater, waste heat 

boilers, and solid waste. 

2.2 Subsequent Regulatory Actions 

We reviewed technology reviews conducted by EPA for other source categories; 

however, none of these technology reviews addressed operations that are similar to the 

Aerospace MACT waste storage and handling affected source. 

 

1

 Technology Transfer Network: Clean Air Technology Center. RACT/BACT/LAER Clearinghouse Basic 

Information. http://www.epa.gov/ttn/catc/rblc/htm/welcome_eg.html. 
In addition, we reviewed the requirements of MACT standards promulgated subsequent 

to the Aerospace MACT (September 1, 1995) for source categories that might be expected to 

generate liquid HAP-containing wastes, such as surface coating, chemical manufacturing, 

printing, and solvent cleaning. We reviewed the following MACT standards (with year of 

promulgation): 

• Subpart U— National Emission Standards for Hazardous Air Pollutant Emissions: 

Group I Polymers and Resins (1996) 

• Subpart DD—National Emission Standards for Hazardous Air Pollutants from Off-Site 

Waste and Recovery Operations (1996) 

• Subpart II—National Emission Standards for Shipbuilding and Ship Repair (Surface 

Coating) (1995, 3 months after the Aerospace MACT) 

• Subpart JJ—National Emission Standards for Wood Furniture Manufacturing Operations 

(1995, 3 months after the Aerospace MACT) 

• Subpart KK—National Emission Standards for the Printing and Publishing Industry 

(1996) 

• Subpart GGG—National Emission Standards for Pharmaceuticals Production (1998) 

• Subpart IIII—National Emission Standards for Hazardous Air Pollutants: Surface 

Coating of Automobiles and Light-Duty Trucks (2004) 

• Subpart MMMM—National Emission Standards for Hazardous Air Pollutants for 

Surface Coating of Miscellaneous Metal Parts and Products (2004) 

• Subpart NNNN—National Emission Standards for Hazardous Air Pollutants: Surface 

Coating of Large Appliances (2002) 

• Subpart PPPP—National Emission Standards for Hazardous Air Pollutants for Surface 

Coating of Plastic Parts and Products (2004) 

Some of these standards address only wastewater (subparts U, KK, and GGG), and others 

include waste coating and solvents in provisions that address a larger universe of materials and 

equipment (subparts II and JJ). 

While subpart DD, the Off-Site Waste MACT, specifically addresses the handling and 

storage of wastes, it was found not to be particularly relevant because the regulated emissions 

points are generally of a type and scale unlike the affected source in the Aerospace MACT. For 

example, subpart DD regulates oil-water separators and surface impoundments. A possible 

exception occurs at the smaller end of the “container” category – covers are required on 

containers as small as 0.1 cubic meter (m3) or about 26 gallons. However, covers do not 

represent improved control over the current Aerospace MACT, as discussed below in section 3. 

The standards that address handling and storage of liquid HAP-containing wastes all 

employ work practice controls similar to the Aerospace MACT. A number include the additional 
requirement to develop and implement a work practice plan to minimize organic HAP emissions 

from the storage, mixing, and conveying of materials that contain such HAP. 

2.3 State and Regional Regulations 

In addition to the RLBC and subsequent regulatory actions, we examined a variety of 

regulations of the Bay Area Air Quality Management District (BAAQMD), the South Coast Air 

Quality Management District (SCAQMD), the Delaware Department of Natural Resources and 

Environmental Control, the Maricopa County (Arizona) Air Quality Department, and the Ozone 

Transport Commission (Northeast United States). These included regulations for the aerospace 

source category; other surface coating operations; coating and ink manufacturing; and other 

processes using solvents, such as solvent cleaning operations, dry cleaning, and degreasing. 

These regulations generally address VOC emissions, rather than volatile organic HAP emissions, 

but in many cases include provisions to reduce evaporative emissions of solvent just as intended 

for the waste storage and handling affected source under the Aerospace MACT. 

Based on the review of these regulations, those that address disposal of VOC-containing 

wastes all employ work practice controls similar to the Aerospace MACT. The review did not 

identify any requirements in these rules that are clearly more stringent than the requirements for 

this affected source under the Aerospace MACT. 

3.0 TECHNOLOGY REVIEW FOR WASTE STORAGE AND HANDLING 

On September 1, 1995, the EPA finalized subpart GG for existing and new major sources 

in the aerospace manufacturing and rework facilities source category. The requirements for 

waste storage and handling promulgated in Subpart GG apply to each waste storage and handling 

operation, which is the total of all waste handling and storage at the facility. Per §63.741(e) in 

subpart GG as promulgated in 1995, all wastes that are determined to be hazardous wastes under 

the Resource Conservation and Recovery Act of 1976 (PL 94-580) (RCRA) as implemented by 

40 CFR parts 260 and 261, and that are subject to RCRA requirements as implemented in 40 

CFR parts 262 through 268, are exempt from the requirements of subpart GG. 

At aerospace manufacturing and rework facilities, waste is produced primarily from 

cleaning, coating, and depainting operations. Cleaning operations produce solvent-laden cloth 

and paper and spent solvent which can emit organic HAP from the evaporation of the solvents. 

Coating operations produce waste paint and waste solvent thinner that also emit organic HAP 

through evaporation. Depainting operations can produce either a liquid or solid waste stream 

depending on the type of process used. Chemical depainting processes produce a liquid sludge 

that consists of the stripper solution and paint residue. Emissions occur from the evaporation of 

the solvent from the stripper solution. Abrasive media blast depainting processes produce a solid 

waste stream that consists of paint chips and spent blasting media. Emissions do not directly 

occur from this waste stream, although particulate emissions are generated during the blasting 

process. 

Section 3.1 presents a summary of the level of control of the 1995 MACT standard and 

the technologies evaluated during this technology review of subpart GG. Section 3.2 presents an 

analysis for identified control measures to determine whether they qualify as “developments in 
practices, processes and control technologies” for waste storage and handling sources at 

aerospace manufacturing and rework facilities. 

3.1 Summary of the 1995 MACT Level of Control 

The Aerospace MACT standard (subpart GG) that applies to the waste storage and 

handling affected source is a work practice standard consisting of housekeeping measures. 

For waste storage and handling operations that are not already subject to requirements 

under RCRA as implemented by 40 CFR parts 260 and 261, and that are subject to RCRA 

requirements as implemented in 40 CFR parts 262 through 268: 

• The provisions under 40 CFR 63.744(a)(1) and (a)(2) require that spent cleaning solvent 

and spent solvent laden materials (e.g., cloth or paper applicators) be stored in closed 

containers. 

• The provisions under 40 CFR 63.744(a)(3) require that all handling and transfer of spent 

cleaning solvents be done in a manner to minimize spills.

• The provisions under 40 CFR 63.748 require that all handling and transfer of HAP 

containing wastes be done in a manner to minimize spills. 

For waste storage and handling operations that are already subject to requirements of 

RCRA as implemented by 40 CFR parts 260 and 261, and that are subject to RCRA 

requirements as implemented in 40 CFR parts 262 through 268: 

• The provisions of 40 CFR 63.741(e) specify that waste storage and handling operations 

are not subject to the requirements of subpart GG. 

Aside from the exemption of RCRA wastes at §63.741(e), the text of the 1995 Aerospace 

MACT does not include any definitions or other descriptions of the operations that comprise the 

waste storage and handling affected source. 

As described in the previous section, waste storage and handling operations are 

characterized by evaporative emissions of organic HAP that are fugitive in nature. Thus, the EPA 

proposed in 1994 organic HAP emissions standards for this affected source, but no standards for 

inorganic HAP. 

Based on the section 114 questionnaire responses collected prior to the proposed rule in 

1994, 181 non-wastewater waste streams were reported. Every stream was controlled by 

housekeeping measures such as keeping the waste material in closed drums. Thus, housekeeping 

measures were established in 1994 as the MACT floor for handling and storage of waste. 

While no data were available for the effect on emissions from the housekeeping 

measures, it was expected that emissions would be reduced based on the data from California 

facilities for keeping cleaning solvents in closed containers. Consequently, housekeeping 

measures were used as the basis for the proposed standard.
In addition, existing RCRA regulations govern handling and storage practices for certain 

types of wastes. Since the EPA did not want to create a situation where 40 CFR part 63, subpart 

GG would be less stringent than RCRA regulations, the proposed rule exempted wastes covered 

under the RCRA regulations. 

The EPA stated at proposal in 1994 that the rationale for the format of the proposed 

standards for handling and storage of waste was essentially the same as that for housekeeping 

measures for cleaning solvents. As stated in section V.F.1 of the 1994 Aerospace MACT 

proposal preamble: “The cleaning operation for which the EPA is proposing standards emits a 

variety of organic HAP. For many of these organic HAP, emission measurement methods either 

do not exist or would be very expensive to implement. In addition, the nature of some cleaning 

operations (e.g., hand-wipe cleaning) makes collection through a conveyance device difficult if 

not impossible. Therefore, the EPA determined that emission standards are not feasible for these 

operations.” Since no data were available to establish an emission limitation and control 

equipment was not technically feasible, a work practice format requiring housekeeping measures 

was selected as the most appropriate means of reducing emissions. 

Based on these considerations, the 1994 proposed and the 1995 final rule included the 

requirement to conduct the handling and transfer of waste in a manner to minimize spills. In 

addition, the 1994 proposal required that all HAP-containing wastes be stored in closed 

containers. However, the EPA received numerous comments that the proposed requirement for 

closed containers was duplicative in light of existing RCRA requirements covering the same 

types of waste materials. The waste materials of concern in the development of the proposed rule 

(such as rags, waste paint and maskant, thinners, sludge, and used paint filters) were already 

subject to the RCRA requirements, according to the commenters. As a result, the EPA deleted 

this provision for storage in closed containers while retaining the provision requiring handling of 

waste in such a manner that minimizes spills. The state of the technology for waste storage at the 

time of the 1995 final rule was storage of waste in closed containers. 

3.2 Identified Control Measures for Waste Storage and Handling

3.2.1 Add-On Control Technology or Other Equipment Not Identified and Considered During 

MACT Development 

As discussed in section 2, the RBLC search and the review of subsequent regulatory 

actions did not yield any new equipment or add-on control technologies that were not considered 

during MACT development. 

3.2.2 Improvements in Add-On Control Technology or Other Equipment (That Was Identified 

and Considered During MACT Development) 

As discussed in section 2, the RBLC search and the review of subsequent regulatory 

actions did not yield any potential developments or improvements in add-on control technology 

or other equipment since the MACT development. 

3.2.3 Work Practices and Procedures Not Identified and Considered During MACT 

Development 
Many of the state and local VOC regulations and MACT standards that were reviewed 

contain work practice standards for waste storage and handling based on housekeeping measures. 

Some of these work practice standards include additional provisions that were apparently 

designed to improve implementation of the housekeeping measures. These work practice 

standards are discussed below. 

Many of the VOC regulations and MACT standards require that VOC/HAP-containing 

waste materials be kept in closed containers. These provisions are most often a component of the 

solvent cleaning requirements, and include the requirement for fresh and spent solvent and 

solvent-laden paper and cloths to be kept in closed containers. In the Aerospace MACT, cleaning 

operations are a separate affected source, and the provisions for that affected source include 

these same requirements. In this way, there is some overlap in the Aerospace MACT between the 

cleaning operations affected source and the waste storage and handling affected source. 

As discussed in section 3.1, the EPA had previously considered requiring all HAPcontaining wastes to be stored in closed containers but decided not to include this requirement in 

the final 1995 rule to avoid duplicating RCRA requirements. Nevertheless, the EPA did retain a 

similar requirement for the cleaning operations affected source. Based on these facts, we do not 

believe that storing all HAP-containing wastes in closed containers qualifies as a “development 

in practices, processes and control technologies” worthy of further consideration in the 

technology review of the waste storage and handling affected source. 

One state rule includes, in addition to a requirement to minimize spills, a requirement to 

clean up spills of fresh and spent cleaning solvent and other VOC-containing material 

immediately. While this measure might produce a marginal reduction in emissions, an effective 

program to prevent spills would be expected to render this requirement moot. In addition, it is 

likely that immediate clean-up of such spills would be required at most facilities under standard 

operating procedures to minimize worker exposure to solvents and for general cleanliness. 

Although not explicitly discussed in the background documents prepared for the Aerospace 

MACT, rapid clean-up of spills is not a new concept, and we do not believe that regulation is 

necessary to induce this practice. Due to these considerations, we do not believe immediate 

clean-up of spills qualifies as a “development in practices, processes and control technologies” 

worthy of further consideration in the technology review of the waste storage and handling 

affected source.