Air Toxics Notebook
Close Vent Systems/Control Devices -  Subpart SS

Applicability: eCFR Subpart SS []

This subpart applies to:
  1. Any of the following that are subject to another NESHAP that references this subpart:
    1. Closed vent systems
    2. Control devices
    3. Routing of air emissions to a fuel gas system or process.

See also Generic NESHAP 40 CFR 63 Subpart YY.

“Generic MACT” standards are consolidated standards designed to cover multiple sources with similar emission types and MACT control requirements. Generic MACT standards are often established when there are less than five (5) facilities nationwide in a source category.

Other MACT standards may reference a Generic MACT. For example, Subpart YY facilities include:
  1. Acetal resins production;
  2. Acrylic/modacrylic fibers production;
  3. Carbon black production;
  4. Cyanide chemical production;
  5. Ethylene manufacturing;
  6. Hydrogen fluoride production;
  7. Polycarbonates production;
  8. Spandex production.
Rules apply to small, area sources? No
Known Sources in NDEQ Jurisdiction: No
Date of Original Final Rule: 6/29/99
Amendments Dates: 04/20/2006 - Amendments
07/22/2002 - Final Rule; Amendments
11/22/1999 - Final Rule; Corrections
06/29/1999 - Final Rule
State Regulations (Title 129): Title 129, Chapter 28, Section 001.32. 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 63.980
Related Rules:

40 CFR Part 63 NESHAP

Subpart TT - Equipment Leaks Level I
Subpart UU - Equipment Leaks Level II
Subpart WW - Storage Tanks Level I
Subpart YY - Generic MACT
Regulations and Federal Registers:
eCFR Subpart SS []

(See attached file: 2S - Fed. Reg. 2006-04-20 - Amendments.pdf)

(See attached file: 2S - Fed. Reg. 2002-07-12 - Final Rule; amendments.pdf)

(See attached file: 2S - Fed. Reg. 1999-11-22 - Final Rule; corrections.pdf)

(See attached file: 2S - Fed. Reg. 1999-06-29 - Final Rule.pdf)

SizeFile Name
172 KB 2S - Fed. Reg. 2006-04-20 - Amendments.pdf
286 KB 2S - Fed. Reg. 2002-07-12 - Final Rule; amendments.pdf
189 KB 2S - Fed. Reg. 1999-11-22 - Final Rule; corrections.pdf
956 KB 2S - Fed. Reg. 1999-06-29 - Final Rule.pdf
Important Dates:
FAQs, Fact Sheets, and Rule Summaries: EPA's Generic MACT Website [] - contains federal register notices and implementation tools
Presentations, Training and Articles:
Other Information and Resources:
Page Last Updated: 3/21/18