Environmental Alert – Clean Air Act Pulse Check: Where EPA’s NSPS OOOOb/c Methane Rules Stand Today

August 31, 2023 | By: Tim Sowecke, Travis Lee, and Tyler A. Self

Despite two years of political and regulatory turbulence, the Environmental Protection Agency’s (“EPA”) New Source Performance Standards (“NSPS”) Subparts OOOOb/c remain in effect and are the dominant framework for regulating methane and volatile organic compound (“VOC”) emissions in parts of the oil and gas sector. Importantly, OOOOb establishes direct federal requirements for new, modified, and reconstructed sources, whereas OOOOc functions through state and tribal implementation plans applicable to existing sources.

The “Pulse Check” on NSPS OOOOb/c
EPA finalized both rules in March 2024, then initiated reconsideration in March 2025 after industry petitions. EPA subsequently finalized targeted revisions to certain temporary flaring and net heating value (“NHV”) requirements and extended many, but not all, compliance deadlines to January 22, 2027 (continuous NHV monitoring got a shorter, 120-day extension). While EPA has signaled more reconsideration rulemaking is coming, that messaging does not amount to a rescission and operators should stay apprised of compliance obligations.

Why the Current Status Matters
NSPS OOOOb/c together substantially widen the regulatory net beyond the older NSPS OOOO/a framework: centralized tank battery compressors, liquids unloading, associated gas from oil wells, pneumatic pumps, and “Super-Emitter” response obligation for third-party detected releases above 100 kg/hr.

Many operators will face periodic electronic reporting through EPA’s CEDRI platform, along with expanded recordkeeping, certification, and reporting obligations, including OGI leak surveys under Appendix K, and expanded requirements applicable to storage vessels. Critically, OOOOc extends methane requirements to existing facilities through state and tribal implementation plans. The mere fact that a facility predates OOOOb does not, by itself, exempt that facility from future OOOOc obligations.

What Operators Should Be Doing Now, Especially for OOOOc
Because OOOOc compliance runs through state plans, Operators should:

Track state-plan development in every jurisdiction where they operate — state-plan requirements and timing will vary.
Run equipment and data-gap assessments for pre-OOOOb assets so potential compliance issues can be identified before state implementation plans become effective.
Build (or automate) recordkeeping systems that can: cover annual certifications, notification deadlines, stakeholder responsibilities across environmental, engineering, legal, and operations teams, and store and process large amounts of data.
Establish a Management of Change procedure so any equipment or process change is checked against both rules before it happens.
Treat permitting as two-directional: prospective compliance for new/modified equipment under OOOOb, retrospective readiness and flexibility for existing equipment under OOOOc.

Key Takeaways
EPA’s ongoing reconsideration and extended compliance deadlines have changed portions of the implementation timeline, but they have not displaced OOOOb/c as the current regulatory framework governing methane emissions from much of the oil and gas sector. For new, modified, and reconstructed sources, OOOOb remains the operative federal standard. For existing sources, the more consequential question may be not whether OOOOc arrives, but how and when state and tribal implementation plans will translate federal requirements into facility-specific obligations. Operators that use this period to close data gaps, strengthen recordkeeping, evaluate legacy assets, and build adaptable compliance systems will be better positioned to respond to future rule changes, state-plan requirements, and enforcement expectations regardless of where EPA’s broader reconsideration ultimately lands.

For assistance with regulatory compliance, permitting, enforcement, and related matters, please contact any member of the Environmental and Natural Resources Team.