This paper examines the efforts of the U.S. pipeline regulator to influence domestic methane emissions. In 2020, the U.S. Department of Transportation’s Pipeline and Hazardous Materials Administration (PHMSA) initiated many actions, ranging from collaboration with stakeholders and Federal and State governments, to rulemaking and enforcement to incentivize reduction of methane emissions from pipeline, liquefied natural gas (LNG) and underground natural gas storage (UNGS) facilities. PHMSA also worked with its domestic and international colleagues to learn from other’s experiences and leverage joint efforts to reduce emissions.

Three years in, PHMSA’s net impact on total pipeline, LNG and UNGS facility emissions is difficult to quantify. Perhaps the greatest impact is influencing the regulator and industry culture about emissions. PHMSA’s regulations have historically allowed pipelines to leak without repair if the released methane was not considered a “hazardous leak.” Prior to 2020, a methane release was only considered hazardous if it posed a threat to humans. PHMSA is considering whether every release should be considered a hazard to the environment, and therefore needing repair or containment.

PHMSA recognizes that methane emissions occur during pipeline and facility failures, and during normal and abnormal operations. Venting 5 miles (8.05 km) of transmission pipeline during normal maintenance is as harmful to the environment as a pipeline failure with valves spaced at an equivalent distance. Pipeline, LNG, and UNGS equipment are often designed to exhale emissions as part of normal operation. The domestic and international community, including governments and industry, can work together to identify and mitigate the most common sources of methane emissions.