Hey, remember that huge natural gas disaster near Los Angeles that state officials declared completely over on February 18? It's not over for the residents of Porter Ranch, many of whom have filed complaints with the LA Department of Public Health since returning to their homes two weeks ago. From October 28 to February 18, the DPH received roughly 700 health complaints related to the natural gas leak at Aliso Canyon, which became the largest such disaster in US history. When Gizmodo spoke with the DPH in December, a toxicology expert explained that the symptoms people were reporting — including dizziness, nausea, headaches and nosebleeds — were the result of acute exposure to mercaptans: acrid, sulfurous compounds that are added to natural gas precisely so that leaks can be detected.
The air at Porter Ranch was so foul that SoCalGas, the company responsible for the leaky well, was forced to relocate some 4400 residents over a period of three months. Now that the leak is plugged, many of those residents have moved back. But to the DPH's surprise, the illness reports continue to roll in. In fact, since February 18, Porter Ranch residents have filed an additional 150 health complaints.
"Given the improvements in environmental conditions, the expectation was that symptom reports would diminish significantly," reads a status report released by the DPH earlier this week. "This presents a unique public health challenge, as the cause of the reported post-sealing symptoms is unclear."
Whatever the cause, the DPH is taking the situation seriously. Tomorrow, it plans to launch a door-to-door checkup throughout the community "to more broadly investigate the nature of health complaints". In conjunction with other state agencies, the DPH is hashing out a plan to monitor indoor air quality, citing concerns that some homes may not have aired out properly since their residents returned.
It's also possible that the outdoor air quality at Porter Ranch is not as good as we initially thought. There's no doubt airborne natural gas concentrations at Porter Ranch have dropped off sharply. But Stephen Conley, the scientific aviation specialist who has been conducing flyovers of Porter Ranch to monitor air quality since November, said that in the days after the well was plugged, a small amount of methane continued to spew out of the ground.
"We don't know whether the emissions we continue to measure come from methane trapped in the ground, the wellhead, or just that the seal wasn't perfect," Conley told Gizmodo in an email on February 25.
The DPH is also fielding concerns about an "oily residue" residents have found on their cars, outdoor furniture and other surfaces in their yards. According to the DPH, initial laboratory analyses showed that this residue consists of long-chain hydrocarbons, similar to those found in crude oil. SoCalGas says that the oil slick does not pose a health risk, but the company has agreed to assess and clean at least 140 homes and four public parks.
Hopefully, state officials will get to the bottom of the health complaints soon so that the residents of Porter Ranch can move on with their lives. Gizmodo has reached out to the DPH and SoCalGas comment but did not hear back by time of publication. For the moment, this community's continued hardship serves as a reminder that major environmental disasters rarely have a quick fix.
Top image: Protestors wearing gas masks attend a hearing over the Aliso Canyon gas leak on January 16. Image Credit: Richard Vogel / AP