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EPA recently released significant rulemaking for the oil and gas sector under proposed NSPS Subpart OOOOa, as well as amendments and updates to NSPS Subpart OOOO. The new rule and amendments will introduce new compliance requirements and alternatives for leak detection and repair (LDAR) at natural gas processing facilities as well as other natural gas sites, such as well sites and compressor stations.

Subpart OOOOa introduces control of methane as well as VOC from equipment subject to the leak provisions of the proposed rule, with the continued use of NSPS Subpart VVa for the leak standards and work practices. This is in line with EPA taking an increased interest in greenhouse gas (GHG) emissions across multiple regulated sectors. The preamble to the proposed rule mentions that “BSER” (best system of emissions reduction) for methane and VOC from equipment leaks is LDAR, using Subpart VVa standards.

EPA also introduces an alternative method of leak detection: optical gas imaging (OGI). Traditionally, LDAR regulations require EPA Method 21 for leak detection. While EPA has not declared that OGI is BSER, the method is being considered as a more cost-effective method of monitoring for leaks. As part of the preamble, EPA has proposed audit procedures to ensure that OGI inspections are rigorous and complete. EPA is currently soliciting comments on whether OGI can or should be used as an alternative to Method 21.

EPA is using this rulemaking to clarify some points about Capital Expenditure in Subpart OOOO. The definition currently points to the definition in NSPS Subpart VVa, which is currently stayed. Therefore, some confusion has existed regarding the accurate and complete definition of Capital Expenditure for the purposes of determining whether Modification has been triggered. EPA is proposing to add a full definition to Subpart OOOO in order to clarify the exact definition of Capital Expenditure.

For natural gas processing facilities, LDAR rules in proposed Subpart OOOOa are the same as current rules in Subpart OOOO, with the addition of methane as a regulated pollutant.

Subpart OOOOa adds LDAR provisions for well sites and compressor stations. EPA is proposing Subpart VVa levels of detection, with semiannual monitoring that could increase to quarterly or decrease to annually depending on leak rates. EPA is currently soliciting comment on LDAR for these affected facilities.