Chemical Manufacturing Area Sources: National Emission Standards for Hazardous Air Pollutants (NESHAP)
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Rule Summary
These national emission standards are for the control of hazardous air pollutants for nine area source categories in the chemical manufacturing sector: Agricultural Chemicals and Pesticides Manufacturing, Cyclic Crude and Intermediate Production, Industrial Inorganic Chemical Manufacturing, Industrial Organic Chemical Manufacturing, Inorganic Pigments Manufacturing, Miscellaneous Organic Chemical Manufacturing, Plastic Materials and Resins Manufacturing, Pharmaceutical Production, and Synthetic Rubber Manufacturing.
The standards and associated requirements for the nine area source categories are combined in one subpart.
On January 8, 2025, the U.S. Environmental Protection Agency (EPA) proposed amendments to the 2009 National Emission Standards for Hazardous Air Pollutants that apply to chemical manufacturing area sources, known as the CMAS NESHAP. An area source is a source that emits fewer than 25 tons per year (tpy) of hazardous air pollutants (HAP) and fewer than 10 tpy of any single HAP.
This action proposes amendments that would reduce emissions of HAP, also known as air toxics, emitted by CMAS including ethylene oxide (EtO), 1,3-butadiene, and ethylene dichloride.
Rule History
03/20/2025 - Notice of Public Comment Period Extension
12/21/2012 - Final Rule; Lift Stay of Final Rule (pdf) (305 KB)
10/25/2012 - Final Rule; Stay (pdf) (198 KB)
01/30/2012 - Proposed Rule; Notice of Reconsideration of Final Rule (pdf) (216 KB)
03/14/2011 - Final Rule (pdf) (144 KB)
12/14/2010 - Proposed Rule (pdf) (154 KB)
12/14/2010 - Final Rule; Stay for Permit Applications (pdf) (145 KB)
10/29/2009 - Final Rule (pdf) (319 KB)
11/20/2008 - Notice of Extension of Public Comment Period (pdf) (139 KB)
10/06/2008 - Proposed Rule (pdf) (262 KB)
Additional Resources
Registered Speakers (pdf) (Feb. 20, 2025 - Virtual Public Hearing)
FAQ: Final Air Toxics Standards for Area Sources in the Chemical Manufacturing Industry (Jan. 31, 2013)
Fact Sheet: Final Air Toxics Standards for Area Sources in the Chemical Manufacturing Industry (Oct. 16, 2009)
View the supporting documents in the docket folder to find additional related documents to this rule.