Air Toxics Notebook
Aerospace Mfg. & Rework Industry -  Subpart GG

Applicability: eCFR Subpart GG [ecfr.gov]

This subpart applies to:
  1. Affected sources that are engaged, either in part or in whole, in the manufacture or rework of commercial, civil, or military aerospace vehicles or components, and that are Major Sources of HAPs*.
Affected sources:
  1. Cleaning operations, including all hand-wipe, spray gun, and flush cleaning operations;
  2. For organic HAP or VOC emissions:
    1. Primer application operationsp;
    2. Topcoat application operations;
    3. Specialty coating application operations;
    4. Depainting operations;
  3. Chemical milling maskant application operations;
  4. Waste storage and handling operations;
  5. For inorganic HAP emissions:
    1. Spray booths;
    2. Portable enclosures;
    3. Hangers which contain a primer, topcoat, or specialty coating application operation subject to §63.745(g), or a depainting operation subject to §63.746(b)(4).
*Major Sources of HAPs emit or have the potential to emit:
  • ≥ 10 tons/year of any single HAP; or
  • ≥ 25 tons/year of total HAPs.
  • Area Sources emit less than Major Sources.

Exemptions to this subpart:
  1. Research and development;
  2. Quality control;
  3. Laboratory testing activities;
  4. Chemical milling;
  5. Metal finishing;
  6. Electrodeposition
    1. except for paint;
  7. Composites processing
    1. except for cleaning and coating of composite parts or components that become part of an aerospace vehicle or component as well as composite tooling that comes in contact with such composite parts or components prior to cure;
  8. Electronic parts and assemblies
    1. except for cleaning and topcoating of completed assemblies;
  9. Manufacture of aircraft transparencies;
  10. Wastewater operations at aerospace facilities;
  11. The rework of aircraft or aircraft components;
    1. if the holder of the Federal Aviation Administration (FAA) design approval, or the holder's licensee, is not actively manufacturing the aircraft or aircraft components;
  12. Parts and assemblies not critical to the vehicle's structural integrity or flight performance;
  13. Primers, topcoats, specialty coatings, chemical milling maskants, strippers, and cleaning solvents that meet the definition of non-HAP material as determined from manufacturer's representations;
  14. Primers, topcoats, and specialty coatings that meet the definition of “classified national security information” in §63.742.

Partial Exemptions:
  1. Primers, topcoats, specialty coatings, and chemical milling maskants in §§63.745 and 63.747 do not apply to the use of low-volume coatings in these categories for which the annual total of each separate formulation used at a facility does not exceed 189 l (50 gal), and the combined annual total of all such primers, topcoats, specialty coatings, and chemical milling maskants used at a facility does not exceed 757 l (200 gal).
  2. Primers, topcoats, and specialty coatings exempted under paragraph (f) of this section and under §63.745(f)(3) and (g)(4) are not included in the 50 and 200 gal limits.
  3. Chemical milling maskants exempted under §63.747(c)(3) are also not included in these limits.
Rules apply to small, area sources? No
Known Sources in NDEQ Jurisdiction: No
Date of Original Final Rule: 9/1/95
Amendments Dates: 08/03/2016 - Direct Final Rule
12/07/2015 - Final Rule
12/08/2000 - Amendments
09/01/1998 - Final Rule
03/27/1998 - Final Rule
12/17/1996 - Corrections
02/09/1996 - Corrections
State Regulations (Title 129): As of September 28, 2022: Title 129, Chapter 13, Section 002. 21

Previously: Title 129, Chapter 28, Section 001.06.

Sources are also responsible for ensuring they are in compliance with current federal requirements found for this subpart in the CFR.
Federal Regulations: 40 CFR 63.741
Related Rules:

NESHAP – 40 CFR Part 63

Subpart MMMM - Misc. Metal Parts and Products
Subpart PPPP - Plastic Parts and Products
Subpart WWWW - Reinforced Plastic Composites Manufacturing
Subpart HHHHHH - Paint Stripping and Misc. Surface Coating (Area Sources)
Subpart XXXXXX - Metal Fabrication (Area Sources)
Regulations and Federal Registers:
eCFR Subpart GG [ecfr.gov]

(See attached file: 2G - Fed. Reg. 2016-08-03 - Final Rule; Amendments.pdf)

(See attached file: 2G - Fed. Reg. 2015-12-07 - Final Rule.pdf)

(See attached file: 2G - Fed. Reg. 2000-12-08 - Final Rule; amendments.pdf)

(See attached file: 2G - Fed. Reg. 1998-09-01 - Final Rule.pdf)

(See attached file: 2G - Fed. Reg. 1998-03-27 - Final Rule; control techniques guidelines.pdf)

(See attached file: 2G - Fed. Reg. 1996-12-17 - Final Rule; Corrections.pdf)

(See attached file: 2G - Fed. Reg. 1996-02-09 - Final Rule; Corrections.pdf)

(See attached file: 2G - Fed. Reg. 1995-09-01 - Final Rule.pdf)

SizeFile Name
206 KB 2G - Fed. Reg. 2016-08-03 - Final Rule; Amendments.pdf
527 KB 2G - Fed. Reg. 2015-12-07 - Final Rule.pdf
258 KB 2G - Fed. Reg. 2000-12-08 - Final Rule; amendments.pdf
160 KB 2G - Fed. Reg. 1998-09-01 - Final Rule.pdf
415 KB 2G - Fed. Reg. 1998-03-27 - Final Rule; control techniques guidelines.pdf
121 KB 2G - Fed. Reg. 1996-12-17 - Final Rule; Corrections.pdf
113 KB 2G - Fed. Reg. 1996-02-09 - Final Rule; Corrections.pdf
377 KB 2G - Fed. Reg. 1995-09-01 - Final Rule.pdf
Forms:
Important Dates:
FAQs, Fact Sheets, and Rule Summaries: (See attached file: 2G - Process & Controls.pdf)

(See attached file: 2G - NDEQ overview.pdf)

Texas CEQ - Rule Flowchart [tceq.texas.gov]

EPA's Subpart GG Website [epa.gov] - contains federal register notices, technical information, guidance documents and compliance tools
SizeFile Name
5,329 KB 2G - Process & Controls.pdf
643 KB 2G - NDEQ overview.pdf
Presentations, Training and Articles:
Other Information and Resources:
Notes:
Page Last Updated: 11/2/22