Since late October 2015, a terrifying amount of methane has been leaking from a well in the Southern California Gas Company's Aliso Canyon facility, not far from the San Fernando Valley community of Porter Ranch. Though the short-term effects of the chemical added to the methane to make it smell like old eggs (so leaks can be more easily detected) have been blamed for all the nausea and headaches that locals have been experiencing, the gas company and public health officials have said that no one needs to worry about long-term health effects. But now it's been revealed that the leak has also introduced more of the cancer-causing chemical benzene into the air than the gas company has previously said—possibly enough to cause problems in the long run, says CBS LA.
Samples taken by the South Coast Air Quality Management District as early as three days after the leak started showed that levels of carcinogenic benzene "hit nearly eight times the regional average," the LA Daily News reports, and the SoCal Gas Company's lab found that the concentrated amount of benzene in the area was over the limit of the state's guidelines seven times in the month of November (when the leak was especially bad because of failed plugging attempts). CBS LA says that the gas company's public communications (FAQs on its website and press releases, since it will not speak to the press) have reported that only two samples of air in the area around the leak showed heightened levels of benzene, but the samples from the two labs have collectively revealed that more than a dozen samples have at least double the amount that "Southern California air regulators consider the normal background level."
The difference likely begins with the gas company, whose website says that a typical amount of benzene in the air in the LA area is 2 parts per billion; according to the South Coast Air Quality Management District, though, it's actually somewhere between 0.1. and 0.5 parts per billion. The state's Office of Environmental Health Hazard Assessment lays out limits for the amount of benzene exposure before associated health risks (like anemia) become more likely; those limits depend on the type of exposure to the chemical: "8 parts per billion for a one-time exposure, 1 part per billion for repeated exposures for eight hours at a stretch, and 1 part per billion for several years or a lifetime."
Though the Southern California Gas Company uses a different background level than the air regulators, it's not clear if that fully explains the disconnect between the agencies' findings and the company's. When asked to clarify, a gas company rep told CBS LA, "I don't know what would explain it."
Whatever the reason, the elevated levels of benzene and their potential to cause long-term health effects are troubling. Though the chances of Porter Ranch residents developing cancer from the amount of benzene presented by the leak is very slim (a million to one), says one expert from UC Berkeley, "studies have shown that exposure of eight hours a day, up to seven days a week, may result in decreasing blood cell counts or other early markers of benzene toxicity," says the LADN. "There's no immediate threat to their health, but I wouldn't want it to happen to my daughter," says the expert.
The state's Office of Environmental Health Hazard Assessment has so far only looked into the short-term dangers of the benzene in Porter Ranch, and not the long-term ones. The amount of gas the well is leaking has dropped since the emissions spiked in November, but there is still a hugely significant amount of methane in the air around the site. The leak isn't expected to be fixed for at least another six weeks.
· Utility May Have Understated Health Threat From Porter Ranch Gas Leak [CBS LA]
· Experts: Porter Ranch residents exposed to carcinogen from gas leak [LADN]
· A Running Count of Exactly How Much Methane is Being Released From Huge Porter Ranch Gas Leak [Curbed LA]
· Attempts to Plug the Enormous Porter Ranch Methane Leak Have Made Things Way Worse [Curbed LA]