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On May 12, 2016, the U.S. Environmental Protection Agency (EPA) issued a final “Source Determination Rule” and the final New Source Performance Standard (NSPS) Subpart OOOOa to reduce methane and volatile organic compounds (VOCs) from new, reconstructed and modified oil and gas sources.  Additional information on each of the finalized rules is provided below.

Source Determination Rule 

The final “Source Determination Rule” was issued to clarify when multiple pieces of oil and gas equipment and activities must be aggregated as a single site with regard to the Prevention of Significant Deterioration (PSD), Nonattainment New Source Review (NNSR), and Title V Operating permit programs (i.e., source aggregation).  Source aggregation of oil and gas production/processing equipment and activities only applies to onshore sources (i.e., offshore operations are not impacted) and will be required if the following three key factors for the equipment and activities are satisfied:


  • Categorized under the same standard industrial classification code, or “SIC code”;
  • Under common control; and 
  • Located on contiguous or adjacent properties (i.e., at the same site or on sites that share equipment and are within ¼ mile of each other).


The entities potentially impacted by this final rule include owners/operators of new and modified operations within the oil and natural gas production and processing segments of the oil and gas sector.  EPA has adopted this change in its permitting rules, but is not requiring state and local permitting authorities with approved programs to adopt the new definitions.  For detailed information on the Source Determination Rule, please visit EPA’s Website:

Final Updates to NSPS OOOOa Rule 

The final NSPS OOOOa rule builds on the 2012 NSPS OOOO requirements by setting emission limits for methane and adding regulations for previously unaffected equipment.  Some major highlights of the rule include the following requirements: 


  1. Leak detection and repair (LDAR) requirements for natural gas well sites and oil well sites, including initial and semiannual leak detection surveys
  2. Emission limits and control requirements for pneumatic pumps at natural gas well sites, oil well sites, and natural gas processing plants
  3. Reduced emission completions (i.e., green completions) at oil well sites with a gas-to-oil ratio greater than or equal to 300 standard cubic feet of gas per barrel
  4. LDAR for boosting and gathering compressor stations and natural gas transmission compressor stations, including initial and quarterly leak detection surveys 
  5. Centrifugal and reciprocating compressor requirements for natural gas transmission compressor stations
  6. Emission limits and control requirements for pneumatic controllers at natural gas transmission compressor stations 
  7. Professional engineer certification requirements for technical infeasibility determinations for controlling pneumatic pumps and for verification of proper closed vent system design


Updates made in the final NSPS OOOOa regulation from the initially proposed NSPS OOOOa version include:


  • Setting a fixed schedule (e.g., quarterly) for leak monitoring rather than a schedule based on performance
  • Allowing Method 21 for finding and repairing leaks as an alternate option to optical gas imaging
  • Encouraging owners/operators to use new technologies to monitor and find leaks
  • Phasing-in of the requirements to use a “green completion” process to capture emissions from hydraulically fractured oil wells, allowing for a six month timeframe for compliance


EPA also finalized the proposed changes to NSPS OOOO within this final rule.  


For more details on the final NSPS OOOOa rule and NSPS OOOO updates, please visit EPA’s Website:

If you have any questions regarding the new rules and how they may affect your future permitting actions or capital projects, please contact your local Trinity office at (800) 229-6655.