Chemical Manufacturing Area Sources: National Emission Standards for Hazardous Air Pollutants (NESHAP)

On this page:

• Rule Summary
• Rule History
• Additional Resources
• Compliance

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 March 28, 2026, the U.S. Environmental Protection Agency (EPA) finalized 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.

Rule History

04/01/2026 - Final Rule

03/20/2025 - Notice of Public Comment Period Extension

01/22/2025 - Proposed Rule

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

Fact Sheet: Final Amendments to the Air Toxics Standards for Chemical Manufacturing Area Sources (pdf) (165.61 KB)

Economic Impact Analysis for the Final National Emission Standards for Hazardous Air Pollutants: Chemical Manufacturing Area Sources

Fact Sheet: Proposed Amendments to the Air Toxics Standards for Chemical Manufacturing Area Sources (pdf) (224.27 KB, Jan. 8, 2025)

Registered Speakers (pdf) (82.11 KB)  (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.

Compliance

Example Initial Notification of Compliance Final Air Toxics Standards for Area Sources in the Chemical Manufacturing Industry