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Emissions Standards Affected by ''Once In Always In'' Policy Change



February 28, 2018

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The U.S. Environmental Protection Agency (EPA) withdrew its “once in always in” guidance on January 25, 2018. As a result of this policy change, a “major source” that limits its potential to emit (PTE) to below major source thresholds can become an “area” source and will no longer be subject to the major source maximum achievable control technology (MACT) standard. This proposed change has the potential to impact companies across industries.

In 2007, EPA drafted regulatory changes to a number of specific National Emission Standards for Hazardous Air Pollutants (NESHAPs) to implement a similar proposed policy change. Any company subject to one of these NESHAPs that is subject to an emissions limitation in its permit or that is considering limiting its emissions through voluntary pollution abatement and prevention efforts or technological innovations could see significant cost savings if compliance with the NESHAP’s reporting and other compliance requirements is no longer required.

  • Subpart F – Synthetic Organic Chemical Manufacturing Industry
  • Subpart G – Synthetic Organic Chemical Manufacturing Industry – Process Vents, Storage Vessels, Transfer Operations and Wastewater
  • Subpart H – Equipment Leaks
  • Subpart N – Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks
  • Subpart O – Sterilization Facilities
  • Subpart R – Gasoline Distribution Facilities (Bulk Gasoline Terminals and Pipeline Breakout Stations)
  • Subpart S – Pulp and Paper Industry
  • Subpart T – Halogenated Solvent Cleaning
  • Subpart U – Group I Polymers and Resins
  • Subpart W – Epoxy Resins Production and Non-Nylon Polyamides Production
  • Subpart Y – Marine Tank Vessel Loading Operations
  • Subpart AA – Phosphoric Acid Manufacturing Plants
  • Subpart BB – Phosphate Fertilizers Production Plants
  • Subpart CC – Petroleum Refineries
  • Subpart DD – Off-Site Waste and Recovery Operations
  • Subpart EE – Magnetic Tape Manufacturing Operations
  • Subpart GG – Aerospace Manufacturing and Rework Facilities
  • Subpart HH – Oil and Natural Gas Production Facilities 
  • Subpart JJ – Wood Furniture Manufacturing Operations
  • Subpart KK – Printing and Publishing Industry
  • Subpart MM – Chemical Recovery Combustion Sources at Kraft, Soda, Sulfite and Stand-Alone Semichemical Pulp Mills
  • Subpart DDD – Mineral Wool Production
  • Subpart GGG – Pharmaceuticals Production
  • Subpart HHH – Natural Gas Transmission and Storage Facilities
  • Subpart JJJ – Group IV Polymers and Resins
  • Subpart LLL – Portland Cement Manufacturing Industry
  • Subpart MMM – Pesticide Active Ingredient Production
  • Subpart NNN – Wool Fiberglass Manufacturing
  • Subpart OOO – Manufacture of Amino/Phenolic Resins
  • Subpart PPP – Polyether Polyols Production
  • Subpart RRR – Secondary Aluminum Production
  • Subpart VVV – Publicly Owned Treatment Works
  • Subpart HHHH – Wet-Formed Fiberglass Mat Production
  • Subpart IIII – Surface Coating of Automobiles and Light-Duty Trucks
  • Subpart JJJJ – Paper and Other Web Coating
  • Subpart KKKK – Surface Coating of Metal Cans
  • Subpart MMMM – Surface Coating of Miscellaneous Metal Parts and Products
  • Subpart NNNN – Surface Coating of Large Appliances
  • Subpart OOOO – Printing, Coating, Dyeing of Fabrics and Other Textiles
  • Subpart PPPP – Surface Coating of Plastic Parts and Products
  • Subpart QQQQ – Surface Coating of Wood Building Products
  • Subpart RRRR – Surface Coating of Metal Furniture
  • Subpart SSSS – Surface Coating of Metal Coil
  • Subpart VVVV – Boat Manufacturing
  • Subpart WWWW – Reinforced Plastic Composites Production
  • Subpart AAAAA – Lime Manufacturing Plants
  • Subpart PPPPP – Engine Test Cells/Stands

Contact Us

Husch Blackwell can help evaluate the potential benefits of this policy’s application to a company’s operations. For more information, please contact a member of Husch Blackwell’s Environmental team or visit our "Once In Always In" Guidance page.


Jason A. Flower


Amy L. Wachs


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