California gas well blowout was largest methane leak in US history

LA smog
CC BY 2.0 Steven Buss/flickr

New study finds Aliso Canyon disaster’s impact equivalent to annual greenhouse gas emissions from over half a million cars.

Here some of us are deciding to ride our bikes in winter and giving up cars altogether in order to be easy on the planet – only to learn that a single natural gas leak will have an impact on the climate equivalent to annual greenhouse gas emissions from over half a million cars, according to a new study. Total emissions during the 112-day event were equal to one-quarter of the annual methane pollution from all other sources in the Los Angeles Basin combined.

As we explained in December (This is the ongoing gas leak in California that's an epic ecological disaster) in the United States old oil fields are commonly used on the premise that geological sites that were good at keeping in oil for millions of years would also be good at keeping in gas – there are hundreds of depleted oil fields now doing service as storage sites for natural gas. The site at Aliso Canyon, owned by Southern California Gas Co., is one of the largest in the country, with a capacity of 86 billion cubic feet. In October the massive underground natural gas storage facility ruptured and methane spewed forth until the leak was finally fixed on February 11.

The new research was conducted by the University of California, Irvine along with the National Oceanic & Atmospheric Administration, UC Davis and others; the team found that during the peak of the disaster, enough methane poured into the air every day to fill a balloon the size of the Rose Bowl, the 12th largest football stadium in the country.

All told, more than 100,000 tons of methane was released, according to the study, confirming that it was the largest methane leak in the nation’s history.

"The methane releases were extraordinarily high, the highest we've seen," says UCI atmospheric chemist Donald Blake, co-author of the study. Blake also looked at surface air samples in the neighboring residential area of Porter Ranch. Samples near homes revealed above-normal levels of benzene, toluene and xylenes – potentially dangerous compounds found in natural gas.

"Some of the volatile organic compounds have been linked to health effects if exposure is long-term," Blake said.

The disaster will substantially affect California's ability to meet greenhouse gas emission targets for the year, the researchers noted. TIme for everyone to get on their bikes and ride.

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