Air quality regulators and Southern California Gas Co. have agreed on a plan to capture and incinerate at least some natural gas from a leaking well that has sickened and displaced thousands of residents of Porter Ranch, according to a legal document filed this week.
Under the plan, the gas company would deploy pollution control equipment as early as next week to burn off both methane, the main ingredient in natural gas, and foul-smelling odorants that are added to the gas for leak detection.
The steps are being proposed to satisfy an administrative order that the South Coast Air Quality Management District is seeking to reduce emissions and odors from the company's Aliso Canyon underground storage facility in the Santa Susana Mountains. For more than two months, a damaged well there has spewed more than 1,000 tons of planet-warming methane a day into the air and sent foul odors into nearby communities.
While state and county officials say emissions from the leak do not pose a long-term health risk, the sulfur-like additives in the gas are causing headaches, nausea, nosebleeds and other ailments.
To minimize those emissions, the gas company plans to use air pollution control devices known as carbon adsorbers and thermal oxidizers to capture and burn off at least some of the gas, using an enclosed flame that is not visible, air quality officials said.
If the plan works, emissions will be reduced but by no means eliminated.
The devices "should help mitigate to some extent the foul odors and also will destroy the methane, but they're not going to be able to capture all the gas that's leaking," air district spokesman Sam Atwood said. He called the pollution control equipment "established technology" that has been in use for decades.
However, the gas company will have to take precautions. State oil and gas regulators say the risk of ignition near the leak is so great that workers are barred from bringing cellphones to the site.
To address that concern, the gas company plans to use pipes to collect gas in a large depression around the leaking wellhead and route it to incineration equipment some distance from the leak, Atwood said.
The piping would carry the gas to "separate units that will remove the fluids from the gas and then either incinerate it or filter the odorant out of it," said Melissa Bailey, a gas company spokeswoman. "The captured odorized natural gas will be combusted by thermal oxidizers that will safely burn the gas in an enclosed, ceramic-insulated chamber."
The system, to be designed and installed in two phases, could incinerate as much as 20 million standard cubic feet of gas per day once it is fully operational, Bailey said.
Paula Cracium, chairwoman of the newly formed Porter Ranch Community Advisory Committee, said she was initially concerned about the proposal to capture and burn some of the gas, but was relieved to hear from company officials at a community meeting Thursday that the incineration would be contained and occur away from the leak site.
"That's a lot less disconcerting than an open flame shooting out from the top of the mountainside," Cracium said. "Once they're able to capture that escaping gas and incinerate it, we're hoping it will greatly diminish the public health impacts on the community."
The 11-page order, filed late Thursday, was prepared jointly and agreed to in advance by the air district and the gas company.
The order would also require the company to fund a health study on the potential effects on the community, to pay for stepped-up air monitoring at the facility and in Porter Ranch, and to continuously monitor the leak with an infrared camera.
Additionally, the gas company would have to improve its leak detection, reporting and inspection practices in order to withdraw the maximum amount of gas from the storage facility "in a contained and safe manner" as quickly as possible. The company would also provide records to air quality regulators, including odor complaints it has received and the amount of gas it has injected and withdrawn from the facility, which can hold 86 billion cubic feet of natural gas.
Activist groups, including Food & Water Watch and Save Porter Ranch, said the proposal falls short of what is needed to protect residents' health, the climate and to guard against future leaks.
Residents have lodged more than 1,600 odor complaints with the air district since the leak began Oct. 23.
The order must be approved by the air district's hearing board. The five-member panel was set to consider the proposal at a court-like proceeding at 9 a.m. Saturday at Granada Hills Charter High School, where it will hear arguments from air district attorneys and sworn testimony from the public.
The gas company said its attorneys will present an opening statement at the hearing.
The air district cited the gas company on Nov. 23 for posing a public nuisance with its odors, about a month after the leak was detected by the company.
As part of the agency's investigation into the leak, air quality inspectors visited the Aliso Canyon facility Dec. 9 and 10 and used an infrared camera to check for leaks, but were unable to inspect the leaking well, called SS-25, for "health and safety reasons."
The inspectors were able to use the camera to assess 16 of the 115 wells that the gas company operates at the site and found 15 of them to be leaking from their valves, fittings and flanges. The leaks, however, were considered "relatively minor" and below levels that would violate the agency's air quality regulations, according to the air district document.
The company later repaired those leaks, the air district said.
After a series of failed attempts to repair the well, the gas company is drilling relief wells in an effort to plug the leak. The utility has said that the process could take until the end of March.
On Monday, the company confirmed that its crews were installing mesh screens to prevent an oily mist at the leaking well from drifting off the site and through the air into nearby communities.
After visiting with Porter Ranch residents this week, Gov. Jerry Brown on Wednesday declared a state of emergency because of the leak and ordered new regulations — including increased inspections and safety measures — for all natural gas storage facilities in California.
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