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National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines

National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines
Basic Information
Code of Federal Regulations Citations
  • 40 eCFR Part 63 Subpart ZZZZ

On this page:

  • Rule Summary
  • Rule History
  • Additional Resources
  • Compliance

Rule Summary

  • Trump Administration Announces Regulatory Interpretation of RICE NESHAP (pdf) (288.81 KB)
  • Duke Energy Request for Regulatory Interpretation of the RICE NESHAP (pdf) (171.53 KB)
  • EPA response to Duke Energy RICE NESHAP Regulatory Interpretation Request (pdf) (269.6 KB)

Stationary engines use pistons that alternately move back and forth to convert pressure into rotating motion. They are used in a variety of applications from generating electricity to powering pumps and compressors in power and manufacturing plants. They are also used in the event of an emergency such as fire or flood.

The key pollutants EPA regulates from these sources includes formaldehyde, acetaldehyde, acrolein, methanol, polycyclic aromatic hydrocarbon (PAH), volatile organic compounds (VOC), carbon monoxide (CO), nitrogen oxide (NOx) and particulate matter (PM).

The National Emission Standards for Hazardous Air Pollutants (NESHAP) for Reciprocating Internal Combustion Engines (RICE) are outlined in the Code of Federal Regulations under 40 CFR 63 Subpart ZZZZ.

Rule History

The following is a timeline of regulatory actions that have formed the current NESHAP for RICE, beginning with the most recent actions.

  • August 30, 2024 - EPA is finalizing amendments to the Clean Air Act rules for stationary engines to add electronic reporting requirements, clarified and corrected inadvertent and other minor errors in the Code of Federal Regulations.
    • Final Rule - August 30, 2024 (pdf) (450 KB)
  • June 26, 2023 - EPA is proposing to amend Clean Air Act rules for stationary engines to add electronic reporting requirements, clarify and correct inadvertent and other minor errors in the Code of Federal Regulations, and solicit comment on a provision that applies to emergency engines.
    • Proposed Rule - June 26, 2023
  • August 10, 2022 - EPA finalized a rule removing the vacated provisions
    • Final Rule - August 10, 2022 (pdf) (269 KB)
  • August 15, 2014 - EPA issued a final decision on reconsideration of the final amendments to the regulations for existing SI RICE
    • Notice for Final Decision on Reconsideration - August 15, 2014 (pdf) (201 KB)
    • Reconsideration of Final Rule - September 5, 2013 (pdf) (218 KB)
  •  January 30, 2013- EPA finalized amendments to the regulations
    • Final Amendments - January 30, 2013 (pdf) (515 KB)
      • Final Rule Amendments Correction - March 6, 2013 (pdf) (211 KB)
    • Proposed Rule Amendments - June 7, 2012 (pdf) (519 KB)
      • Reopening the Comment Period - October 3, 2012 (pdf) (214 KB)
      • Notice of Public Hearing and Extension of Public Comment Period - June 21, 2012 (pdf) (195 KB)
  • August 20, 2010 - EPA finalized regulations for existing stationary spark ignition (SI) RICE
    • Final Rule - August 20, 2010 (pdf) (384 KB)
  • March 3, 2010 - EPA finalized regulation for the existing stationary compression ignition (CI) RICE
    • Final Rule - March 3, 2010 (pdf) (296 KB)
    • Final Rule Correction - June 30, 2010 (pdf) (142 KB)
    • Proposed Rule - March 5, 2009 (pdf) (267 KB)
      • Extension of Public Comment Period - April 14, 2010 (pdf) (140 KB)
    • Advanced Notice of proposed Rulemaking - January 24, 2008
  • January 18, 2008 - EPA finalized regulations for new RICE less than or equal to 500 HP located at major sources and new RICE located at area sources
    • Final Rule - January 18, 2008 (pdf) (338 KB)
    • Proposed Rule -June 12, 2006 (pdf) (349 KB)
      • Proposed Rule Correction - June 26, 2006 (pdf) (127 KB)
      • Extension of Public Comment Period - July 27, 2006 (pdf) (143 KB)
  • June 15, 2004 - EPA finalized the first regulation for stationary RICE greater than 500 horsepower (HP) located at major sources of HAP
    • Final Rule - June 15, 2004 (pdf) (346 KB)
    • Proposed Rule - December 19, 2002 (pdf) (309 KB)

Additional Resources

  • Technical Documents
  • Fact Sheets
  • Implementation Tools
     

Compliance

  • Compliance Summary Tables

Stationary Engines

  • Basic Information
  • Regulatory Actions
  • Compliance Requirements
  • Tools to Help You Comply
Contact Us About Stationary Engines
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Last updated on May 8, 2025
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