Aliso Canyon leak sheds light on national problem

Gaping holes in U.S. regulatory safety net allow methane leaks to go unchecked

Aliso Canyon
Aerial infrared imaging shows methane leaking at a SoCal Gas storage facility. Methane is a potent greenhouse gas. VIDEO: Watch the footage.
What happened?
On Oct. 23, 2015, a massive natural gas leak was discovered at a storage well near Los Angeles. After attempts to plug the leak were unsuccessful, SoCal Gas began building a relief well to capture the leaking gas. In mid-February, the leak was fixed, according to state officials.

How big was the leak?
“It was a mega-leak, one of the biggest ever recorded,” says Tim O’Connor, California Oil & Gas Director. EDF estimates that the amount of methane leaked had the same 20-year climate impact as burning nearly a billion gallons of gasoline.

Aliso Canyon leak: Estimated impact


metric tons of methane, a powerful climate pollutant, are estimated to have leaked between Oct. 23 and Feb. 11.

That’s the same as:

Leaked methane: Estimated impact


metric tons of methane, a powerful climate pollutant, are estimated to have leaked between Oct. 23 and Feb. 11.

That’s the same as:



metric tons of carbon dioxide released



gallons of gasoline burned



dollars worth of natural gas wasted

Methane: Potent climate polluter

Methane is a strong greenhouse gas that carries 84 times the warming power of carbon dioxide in the initial decades after it is released.

“Emitting just a little bit of methane greatly accelerates the rate of climactic change,” says EDF Chief Scientist Steven Hamburg.

How common are methane leaks?

Very. Aliso Canyon is a particularly egregious example of a problem that’s happening every day across the country. Our extensive research effort revealed that methane is leaking at every stage of the oil and gas supply chain.

The EPA has begun to limit this pollution, but most pollution continues unchecked.

These leaks aren’t just happening at big oil and gas facilities or in oil fields. Our mapping project with Google Earth Outreach showed that leaks are a problem even in neighborhoods, where many small leaks add up to a big climate problem.

Methane leaks in Chicago area

Chicago leaks: Our readings indicate about one methane leak for every three miles of roadways we drove.

Why are leaks happening?

It’s a combination of oil and gas companies failing to monitor and maintain aging infrastructure and a lack of oversight of the oil and gas industry. For too long, we have gone without federal and state standards that require sufficient leak and safety inspections for oil and gas facilities, and industry has shown it can’t be trusted to fix the problem on its own.

When leaks do occur, they may go unnoticed indefinitely, since methane is colorless and odorless.

“This is partly why methane leaks across the oil and gas supply chain have gone unaddressed for so long—because, unlike an oil spill, it’s not immediately apparent to the general public that something’s amiss,” says Mark Brownstein, Vice President of EDF’s climate and energy program.

What’s the solution?

Officials must take a serious look at stronger standards that require basic, low-cost improvements, inspections and leak detection to prevent these types of problems in the future.

The good news: The EPA finalized national rules that will, for the first time, directly regulate oil and gas methane emissions. The bad news: These rules are under attack from the Trump administration, who has moved to delay these vital health protections.

What can I do to help?

Voice your support for strong national standards for oil and gas methane emissions—from all sources.

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