(California) Greenhouse Gas Emission Standards for Crude Oil and Natural Gas Facilities

Last updated: 18 May 2022

The regulation establishes greenhouse gas (including methane) standards for onshore and offshore oil, natural gas production sites; crude oil, condensate, and produced water separation and storage; underground gas storage; and natural gas gathering and boosting stations, processing plants, and transmission compressor stations. 


• Larger separators and tank systems (at least 100 bbls, receiving at least 50 bbl of crude oil or condensate or 200 bbl produced water/day) must conduct flash testing by 1 Jan 2018 or within 90 days of installation.  By 1 Jan 2018, install vapour collection systems at new separator and tank systems emitting > 10 metric tons/yr; control existing systems of that size by 1 Jan 2019. Smaller systems: report flash test results annually. 

• Owners of circulation tanks for well stimulation shall implement a best practices management plan to limit methane emissions. By 1 Jan 2019, owners shall submit a technology assessment for capturing 95% of tank vapour; based on regulator feedback, install by 1 Jan. 2020.

Reciprocating gas compressors that operate at least 200 hours/yr at a production facility, including rod packing and seals, shall undergo LDAR. Beginning 1 Jan 2019, owners must repair leaks within 30 days (or seek delay). Owners shall record leak concentrations and report once a year.

Reciprocating gas compressors at natural gas gathering and boosting stations, processing plants, transmission compressor stations, and underground gas storage facilities shall undergo LDAR. Rod packing and seals shall be measured annually by a metered vent stack. Beginning 1 Jan 2019, control vent stacks with a vapour collection system, and repair compressors  within 30 days if they emit > 2 standard cubic feet per minute (scfm).

Centrifugal natural gas compressors that operate at least 200 hours in a year shall undergo LDAR beginning 1 Jan 2018. Wet seals shall be measured annually through a metered vent stack. Beginning 1 Jan 2019, control vent stacks with a vapour collection system; repair compressors emitting > 3 scfm within 30 days (approval for delays possible) or replace by 1 Jan 2020.

Natural gas pneumatic devices and pumps – Beginning 1 Jan 2018, intermittent bleed devices should undergo LDAR. Beginning 1 Jan 2019, pneumatic pumps and continuous bleed devices shall undergo LDAR and cease venting (devices installed before 1 Jan 2016 may continue if tested annually and emissions are < 6 scfh). Eliminate venting by vapour collection, or by replacing devices with compressed air or electric versions.

• Operators shall collect vented natural gas from liquids unloading by 1 Jan 2018, or directly measure or calculate the amount of vented natural gas and report to the regulator.

• Operators shall take direct measurements annually from all well casing vents by 1 Jan 2018.

Underground gas storage (UGS) facilities shall have a leak detection protocol. By 1 Jan 2018, they shall submit a monitoring plan for approval (rule includes minimum requirements for monitoring including placement of sensors and alarm sensitivity).


Generally, LDAR requires daily audio-visual inspection of some components (weekly for facilities not visited every day), and quarterly using EPA Method 21 (OGI can only be used to screen). Initially (1 Jan 2018 through 31 Dec 2019), repairs required in 14 days for leaks of at least 10,000 ppmv (5 days if 50,000 ppmv). Beginning 1 Jan 2020, repairs required in 14 days for leaks of 1,000 ppmv (5 days if 10,000 ppmv). Hatches shall remain closed; open-ended lines must be capped.


For 5 years, operators must keep records of flash testing; separator and tank system throughput; rod packing leak concentrations and flow rates; wet seal flow rates; pneumatic device flow rates; volumes of gas vented during liquids unloading; well casing vent flow rates; UGS leaks; and LDAR inspection results. 


Enforcement provisions make clear that each violation, each day of violation, and each metric ton of methane emitted in violation, constitutes a “single, separate violation” of the law.


The regulator is the California Air Resources Board.

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