What Colorado Adopted

The Air Quality Control Commission adopted equipment-specific revisions and approved submission of Colorado’s Clean Air Act Section 111(d) plan to EPA. Earlier phases addressed pneumatic equipment, compressors and leak detection and repair. The September phase adds or refines requirements for enclosed combustion devices, open-tip flares, closed vent systems, covers, storage vessels, associated gas and vapor recovery units.

State adoption and EPA approval of the plan are separate steps. EPA’s ongoing federal reconsideration does not, by itself, remove Colorado’s state requirements. Operators should evaluate the adopted state provisions together with their applicable federal standards and permit conditions.

On October 7, 2026, EPA announced plans to propose further revisions to the federal OOOOb and OOOOc rules, including provisions for certain well sites, the Super Emitter Program, covers and closed vent systems, associated gas, and control devices. The announcement itself does not amend Colorado’s Regulation 7. Operators should continue evaluating applicable state requirements and permit conditions while monitoring the federal rulemaking.

Where NHV Requirements Apply

NHV measures the usable heat content of a gas stream and helps establish whether the gas can support effective combustion. Part B, Section II.I.2.f.(i) of the adopted rule specifies the following minimum vent-gas values for covered open-tip flares at natural gas-processing plants.

These limits apply within the gas-plant provisions. The rule also allows an EPA-approved alternative test method. Facilities should confirm the applicable compliance pathway before selecting sampling or monitoring equipment.

Enclosed Combustor Monitoring and Testing

For enclosed combustion devices, the September revisions focus on inlet gas flow, pressure actuator systems, flame operation and visible emissions. Where flow meters are used, covered operators must measure hourly inlet flow and keep the flow within the manufacturer’s specified range or a range established through an approved performance test. Pressure actuator systems have their own calibration and annual verification requirements.

The revised flow and pressure provisions generally begin April 1, 2027. Specified storage tanks that are subject to state controls but are not storage vessel designated facilities have an April 1, 2028 date. The rule also phases out the technical or economic infeasibility exemption for installing a flow meter or pressure actuator system on November 14, 2026, while retaining other specified exceptions and approved alternatives.

Colorado already requires performance testing for certain enclosed combustion devices to demonstrate at least 95% hydrocarbon control efficiency. That obligation predates the September adoption. Operators should review testing schedules, approved protocols and any corrective-action or retesting requirements alongside the revised operating provisions.

Closed Vent Systems and Tank Covers

Beginning April 1, 2027, the adopted rule establishes additional requirements for covered closed vent systems and covers. These provisions address emission capture, bypass controls, inspection of connections and sealed openings, and compliance records. They also reach storage tanks controlled under Colorado’s state program, including tanks outside the federal designated-facility category.

For qualifying new installations, initial instrument-based inspections are required within 30 days of routing emissions through the closed vent system or startup following cover installation. Subsequent closed vent system inspections are integrated into the facility’s required LDAR program. Operators should check hatches, gaskets, connections and bypass arrangements as part of that work.

LDAR and Compressor Emissions

The adopted Regulation 7 text carries forward the gas-plant LDAR and compressor provisions addressed in the earlier rulemaking phases. For covered gas-plant components, the LDAR program provides an Appendix K optical gas imaging option every other month or a Method 21 option with component-specific inspection frequencies. Applicability exceptions remain.

Covered compressor provisions include emissions screening or volumetric vent measurements, repair thresholds and verification after repair. For reciprocating compressors using the measurement pathway, a rod-packing rate above 2 standard cubic feet per minute per cylinder triggers repair or replacement. Applicable methods and alternatives must be checked for each compressor.

What Operators Should Review Now

A useful first step is to map each facility’s equipment to its state requirements, federal subpart and permit conditions. An open-tip flare at a processing plant, an enclosed combustor controlling a tank, and a compressor vent can have different testing methods and deadlines. Treating them as one monitoring category can leave gaps in a compliance plan.

Operators should confirm combustion-device specifications and flow ranges, review performance-test records, and identify whether tank covers or closed vent systems need inspections or repairs. Gas plants should check their LDAR procedures against the applicable Appendix K or Method 21 requirements. Compressor inventories should include the information needed to select an allowed measurement method and schedule any follow-up work.

The gas-plant program in Section II.I.2 generally begins January 1, 2027. For process unit equipment already subject to OOOO or OOOOa, the adopted text instead specifies 12 months after EPA approves Colorado’s Section 111(d) plan; OOOOb equipment is excluded from that section. Compressor provisions have separate timing and applicability rules. The September adoption date should not be used as a universal compliance deadline.

Encino recommends reviewing gas capture, combustion performance and inspection records together so that the compliance plan reflects how the equipment operates as a system. Our testing, LDAR and regulatory teams can help operators identify applicable obligations and plan the work needed to document compliance.