EPA published a final rule revising two technical provisions of the 2024 OOOOb/OOOOc framework in the Federal Register on April 9, 2026 [1]. The revisions address temporary flaring provisions for associated gas at oil wellsites and net heating value (NHV) monitoring requirements for flares and enclosed combustion devices [2]. The rule took effect June 8, 2026 and remains in effect, though environmental groups have petitioned a federal appeals court for review.

Both changes are narrow in scope and leave all other OOOOb/OOOOc provisions and requirements intact as established in 2024 [2]. The temporary flaring revision extends the baseline flaring window; the NHV revision exempts most flares and combustion devices from monitoring [2]. The revisions affect operators across all producing regions subject to OOOOb or OOOOc, particularly those managing associated gas disposal or combustion device compliance. Operators evaluating the amendments should do so independently of broader OOOOb/OOOOc developments.

This post is for informational purposes only and does not constitute legal or compliance advice. Consult qualified legal counsel or a compliance professional for guidance specific to your operations and jurisdiction.

What Does the April 2026 Amendment Change?

The April 2026 amendment revises two specific technical requirements within the OOOOb/OOOOc framework while leaving all other provisions intact [2]. EPA characterized the action as a burden-reduction measure targeting provisions where compliance costs exceeded the agency’s original estimates [2]. EPA projects $2.5 billion in compliance cost savings from 2024 through 2038, about $208 million per year [3]. No other OOOOb/OOOOc requirements were modified [2].

The Amendment Expands Temporary Flaring for Associated Gas

The revised provision extends the baseline temporary flaring limit for associated gas at oil wellsites from 24 hours to 72 hours [2]. The window tripled. It also adds an exigent-circumstances allowance when weather, site hazards, or personnel shortages block timely equipment repairs [2]. Under the 2024 standards, operators had to route associated gas to a sales line or use it on-site within a compressed timeline [4].

Operators managing equipment malfunctions at remote wellsites gain the most flexibility from the longer window. Operators should confirm how the revised rule defines an exigent circumstance before relying on the extended window.

EPA Narrows the NHV Monitoring Requirement

The rule exempts most flares and enclosed combustion devices from NHV monitoring based on high heating-value content [2]. It retains monitoring only where inert gases are added or other scenarios lower the inlet stream’s heating value [2]. Typical triggers include acid gas removal, glycol dehydration, and CO2 flooding at enhanced-recovery sites [2]. The exemption is broad.

The 2024 standards already allowed a periodic sampling demonstration as an alternative to continuous NHV monitoring [4]. That alternative required a 14-day sampling demonstration plus periodic resampling over five years [4]. Sources adding inert gases such as CO2 or nitrogen must still monitor NHV under the revised rule [2]. The earlier June 1, 2026 continuous-monitoring compliance date was superseded for exempt sources when the rule took effect.

What Should Operators Evaluate if OOOOb/OOOOc Remains in Effect?

Two evaluations matter most if OOOOb/OOOOc remains in effect: which combustion devices are covered, and whether any trigger retained NHV monitoring [2].

Note: OOOOb/OOOOc remains in effect but is under challenge in federal court; the steps below apply only while the rule stands. Confirming the rule’s current status before acting on these evaluations reduces compliance exposure.

The first step is determining which combustion devices at a facility are subject to the NHV monitoring requirement under OOOOb or OOOOc [2]. Not all flares and enclosed combustion devices are covered [4].

Applicability is narrower than the rule’s general scope suggests. Applicability depends on source category and affected facility status under the 2024 rule [4].

Whether a device adds inert gases determines if NHV monitoring still applies after the exemption [2]. Facilities with acid gas removal, glycol dehydration, or CO2 flooding are the likeliest to still need it.

Any facility planning to use the temporary flaring provision should confirm that qualifying conditions in the revised rule match operational circumstances at each wellsite [2]. Documentation of the qualification basis should be prepared before the compliance date. Inadequate documentation creates audit exposure even when the underlying conditions are met.

What Did Not Change?

All other OOOOb/OOOOc provisions remain as established in 2024, subject to the rule’s current uncertain status [5]. The April 2026 amendment does not modify leak detection and repair (LDAR) requirements or pneumatic controller phase-down schedules [2]. Well liquids unloading standards are also unchanged [2].

The April 2026 OOOOb/OOOOc amendment is also separate from the federal GHGRP Subpart W reconsideration [2]. EPA is separately reconsidering whether to suspend mandatory GHGRP Subpart W reporting for reporting years 2025 through 2034. For a detailed breakdown, see: GHGRP Subpart W Reporting in 2026: What Is Still Required.

Whether the full OOOOb/OOOOc framework survives the pending court challenge is a separate question. A targeted cost-reduction amendment is not the same thing as a signal about the full framework’s future.

Tracking OOOOb/OOOOc developments independently of this specific amendment remains warranted.

A cost-reduction amendment two years after OOOOb/OOOOc’s finalization is not a typical EPA rulemaking sequence.

Colorado’s ONGAEIR program and other state-level reporting obligations are unaffected by this federal amendment [6]. Operators with overlapping state and federal obligations should evaluate each program on its own terms.

Colorado ONGAEIR deadlines and preparation guidance are covered separately [6]. For a detailed breakdown of ONGAEIR preparation timelines and deadlines, see: Colorado ONGAEIR Due June 30: A Practical Filing Checklist [6].

Frequently Asked Questions

Which Combustion Devices Must Still Monitor NHV After the Exemption?

The revised rule exempts most devices but requires NHV monitoring where inert gases are added to the vent stream [2]. Acid gas removal units, dehydrators, and CO2 flood operations are typical triggers. Where monitoring still applies, sampling frequency, analytical methods, and documentation formats are specified in the rule text and vary by device type [2].

How Does the April 2026 Amendment Interact with State-Delegated NSPS Programs?

States with EPA-delegated authority implement federal NSPS standards, including amendments, within their own programs [7]. Timing varies by state. Until a delegated state updates its own regulations, operators may face a gap between the federal amendment and the state-adopted version of OOOOb/OOOOc. Operators in delegated states should confirm with their state agency whether the April 2026 revisions have been incorporated into the state program.

Can Operators Who Already Installed Continuous NHV Monitors Switch to Periodic Sampling?

The April 2026 amendment permits operators with existing continuous monitors to continue using them [2]. Where their device is now exempt, they may stop NHV monitoring altogether [2]. Where monitoring is retained, the 2024 periodic sampling demonstration remains available as an alternative [4]. Continuous NHV monitoring provides higher-resolution data at greater cost than periodic sampling; the right choice depends on facility configuration and data needs.

Does the April 2026 OOOOb/OOOOc Amendment Affect State-Level Flaring Regulations?

State flaring programs operate independently of federal OOOOb/OOOOc requirements. Colorado, New Mexico, and Texas each maintain separate flaring and venting requirements with distinct applicability thresholds and timelines [8]. A relaxation at the federal level does not necessarily change an operator’s compliance posture in a given state where state rules are more stringent.

What NHV Sampling Frequency and Recordkeeping Does EPA Require Under the Periodic Alternative?

Records must be retained for five years under standard OOOOb/OOOOc recordkeeping provisions [4]. Required records include the date, time, and NHV result of each sample where monitoring applies [2]. Sampling frequency must be sufficient to demonstrate the vent gas meets the applicable NHV threshold [2]. Device-specific sampling protocols, including minimum sample counts and analytical methods, are defined in the final rule text and vary by device type [2].

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References

  1. EPA. Final Rule: Reconsideration of Standards of Performance for New, Reconstructed, and Modified Sources and Emissions Guidelines for Existing Sources: Oil and Natural Gas Sector Climate Review. 91 FR 18056. Published April 9, 2026. Effective June 8, 2026.; DATE-SENSITIVE - OOOOb/OOOOc subject to potential repeal or stay, verified July 2026.
  2. EPA. Final Rule: Reconsideration of Standards of Performance for New, Reconstructed, and Modified Sources and Emissions Guidelines for Existing Sources: Oil and Natural Gas Sector Climate Review. 91 FR 18056. Published April 9, 2026. Effective June 8, 2026.
  3. EPA. Economic Impact Analysis: Final Reconsideration for Two Technical Aspects of the 2024 Final Clean Air Act Rule. April 2026.
  4. 40 CFR Part 60, Subpart OOOOb. Standards of Performance for Crude Oil and Natural Gas Facilities: Oil and Natural Gas Sector Climate Review. 2024 Final Rule.
  5. EPA. Final Rule: Reconsideration of Standards of Performance for New, Reconstructed, and Modified Sources and Emissions Guidelines for Existing Sources: Oil and Natural Gas Sector Climate Review. 91 FR 18056. Published April 9, 2026. Effective June 8, 2026.; DATE-SENSITIVE - verified July 2026.
  6. Colorado Department of Public Health and Environment (CDPHE). ONGAEIR Program, Colorado Air Quality Control Commission Regulation 7.
  7. Clean Air Act Section 111(c); 40 CFR 60.4. NSPS implementation is delegated to states, which incorporate federal amendments into their own programs.
  8. Colorado Department of Public Health and Environment (CDPHE). ONGAEIR Program, Colorado Air Quality Control Commission Regulation 7. New Mexico Environment Department (NMED). 20.2.50 NMAC: Oil and Gas Sector Ozone Precursor Pollutants. Texas Railroad Commission. Statewide Rule 32 (16 TAC §3.32): Gas Well Gas and Casinghead Gas Shall Be Utilized for Legal Purposes.