A massive natural gas leak in the hills above suburban Porter Ranch in 2015 spewed more than 110,000 metric tons of methane and other toxic chemicals into the San Fernando Valley atmosphere, the biggest natural gas leak in U.S. history.
The blowout lasted more than 100 days, forcing thousands of residents to evacuate while Southern California Gas Co., which stored its natural gas in vast underground caverns, tried to cap the leak. The disaster set off demands that the gas company stop storing gas in another populated area, under Playa del Rey.
Now, eight years after the Valley blowout, researchers at UCLA will use numerous data sources to measure the impact of the disastrous gas leak on those living in nearby communities, as part of its Aliso Canyon Disaster Health Research Study.
The UCLA team will analyze data on adverse pregnancy and birth outcomes, cancer, hospital admissions and emergency room visits. Researchers also will collect new data that involves an in-person clinical exam, and they will conduct extensive surveys on the physical and mental health of residents impacted by the blowout.
Nearly 10,000 families were forced to leave their homes for five months to escape the poisonous methane leak, and the disaster resulted in a $1.8 billion settlement from SoCalGas to 35,000 victims.
“We’re going to examine changes in a health and mental health status that occurred after the blowout disaster,” said Michael Jerrett, professor at the Department of Environmental Health Sciences in the Fielding School of Public Health at UCLA, and a principal investigator in the study, during a Zoom meeting on Nov. 14.
The five-year health study, which started last year, is funded by a $119.5 million settlement reached by the state and local officials with SoCalGas in 2018, which allocated $25 million for a health study.
A team of about 50 researchers will investigate the health impacts on pregnant women, children and adults during and after the disastrous 2015 gas leak, according to Jerrett.
About 105 residents had their blood drawn following the blowout and their results are still available to researchers, according to Jerrett.
Researchers will offer participants of the study an extensive questionnaire about physical and mental health experiences and their well-being. They will also collect blood from nearly 600 adults from the impacted zone and the area outside it to analyze for potential impacts of exposure to the gas leak.
One of the goals of the study will be an assessment of the composition and the amount of emissions released from the facility, Jerrett added.
“We’re trying to understand where the emissions landed and how those were translated into exposures in human populations that were affected by the disaster or could be affected by ongoing emissions,” he said.
Lori Tessier of Porter Ranch was one of many residents of communities impacted by the gas leak who joined the meeting to ask questions and share her feedback.
During the blowout there were days, Tessier said, she didn’t smell any particular odor but still experienced “extreme health systems and felt terrible.” She wondered whether some of the substances that residents were exposed to during the five-month gas leak contained metals.
Jerrett said his team had data with measurements taken during the blowout and they found “some elevated levels of benzene and hexane in residents who have been affected.”
In the coming months, researchers will be conducting indoor and outdoor air monitoring within the community impacted by the gas leak and the zones outside impacted areas.
“Will be also sampling raw natural gas and doing analysis of the composition, so we can better understand the gas that is likely being stored in the Aliso facility,” Jerrett said. “That will help to inform our house studies, our risk assessments and also our atmospheric modeling.”
