The Trump administration has been working to rollback rules instated by the Obama administration that would limit how much methane gas could be vented to the atmosphere at oil- and gas-drilling and processing operations. In a press release today, the Environmental Protection Agency (EPA) announced that it is proposing to relax Obama-era rules, saving the industry $484 million in avoided energy costs.

But the EPA is expected to justify its rules with analysis. That analysis (PDF) suggests that this regulatory rollback will also come with costs in the form of 308,000 short tons of methane emitted between 2019 and 2025. For context, the Aliso Canyon gas leak three years ago represented the largest accidental release of methane in US history, and over the four months that workers struggled to plug that well, 107,000 short tons of methane are estimated to have been released.

That is a serious amount of methane with serious climate consequences in the short-run. Methane is many times more potent than CO 2 as a greenhouse gas, though it decomposes in the atmosphere more quickly. Carbon dioxide sticks around in the atmosphere for a longer time, but each individual molecule of CO 2 has less of a warming effect than a molecule of methane.

The EPA's own analysis also says than an additional 100,000 short tons of volatile organic compounds and 3,800 short tons of hazardous air pollutants would also be emitted, compared to keeping the existing rules in place.

Latch-key emissions

Under the Obama-era rules, oil- and gas-drilling companies and processors face requirements to monitor their methane emissions quarterly, searching for leaks that could be quietly releasing pollutants into the air. Under the newly proposed rule, the EPA only wants oil and gas companies to search for leaks semi-annually or annually. A recent study suggested that methane leaks from oil and gas infrastructure are dramatically underestimated, nearly (but not quite) to the point where burning natural gas is as harmful to the environment from a climate perspective as burning coal.

The EPA's current proposed action would (PDF) not only reduce the frequency with which the oil and gas industry would have to monitor for methane leaks, it would also relax requirements for companies to have a professional engineer certify that methane emissions regulations had been met. In addition, the EPA's fact sheet suggests that the agency is considering extending the time a company has to complete an initial emissions survey after a well is placed. Currently, the rules require that a well operator has 60 days to monitor for emissions. No precise extended time period has been suggested. The EPA also suggested giving the oil and gas industry extra time to repair any gas leaks that are found.

The Trump administration has faced several legal challenges on the matter of these methane rules. The EPA under former Administrator Scott Pruitt tried to simply not enforce the Obama-era rules while it prepared the analysis for a more efficient regulatory rollback, but the agency was ordered to enforce those rules by the US Court of Appeals in 2017.

The EPA will hold a public hearing on the proposed rules in Denver, Colorado, at a date that's still to be determined.