Methane: https://en.wikipedia.org/wiki/Methane
/? methane emissions rules: https://www.google.com/search?q=methane+emissions+rules
From https://www.epa.gov/newsreleases/biden-harris-administration... :
> Oil and natural gas operations are the nation’s largest industrial source of methane. Methane is a potent greenhouse gas that traps about 80 times as much heat as carbon dioxide, on average, over the first 20 years after it reaches the atmosphere and is responsible for approximately one third of the warming from greenhouse gases occurring today. Sharp cuts in methane emissions are among the most critical actions the U.S. can take in the short term to slow the rate of climate change. Oil and natural gas operations are also significant sources of other health-harming air pollutants, including smog-forming volatile organic compounds (VOCs) and toxic air pollutants such as benzene.