Nearly four months after it was first detected, officials announced Thursday a leak of natural gas from a Southern California Gas Co. storage well in Porter Ranch has been permanently capped.
The utility temporarily stopped the leak last week by building a relief well more than 8,600 feet long and was injecting cement into the faulty well at the Aliso Canyon Storage Facility for a permanent cap.
Local, state and utility officials made the announcement at a news conference on Thursday.
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"We have good news," said Jason Marshall, chief deputy director of the California Department of Conservation Division of Oil, Gas and GeoThermal Resources. "The leak in Aliso Canyon storage field is permanently sealed."
Final tests on the integrity of the cement cap were completed late Wednesday and air quality in the area has returned to normal levels, said Marshall, noting the California Air Resources Board and South Coast Air Quality Management District had also confirmed the flow of gas had stopped.
Thousands of families who relocated to temporary housing to get away from the noxious smell will have eight days to move back. People living in temporary housing with extended leases will have until those leases run out to return home.
"While the leak has been stopped and the well permanently sealed, we have much work to do, partnering with state and local agencies to help the local community and impacted residents return to normal," said Dennis V. Arriola, chairman, president and CEO of SoCalGas.
Arriola added that the utility started inspection of the other wells at Aliso Canyon to verify those could be operated safely in the future and that operations will shift to determining the cause of the leak.
The blowout at the largest natural gas-storage facility in the West was first detected on Oct. 23, and has spewed more than 2 million tons of climate-changing methane.
Residents have complained of headaches, nausea, nosebleeds and other symptoms. Public health officials blame the woes on an odorant added to the gas and said there shouldn't be long-term health problems.
Governor Jerry Brown has declared a state of emergency because of the leak, and SoCalGas is facing nearly a dozen lawsuits from regulators, residents and the city.
On Wednesday, SoCalGas pleaded not guilty to misdemeanor charges involving reporting of the leak to authorities and discharging contaminants into the air.
The company is charged with three counts of failing to report the release of hazardous materials from Oct. 23 to Oct. 26, and one count of discharging air contaminants, beginning Oct. 23 and continuing for the duration of the leak.
"We do not believe a criminal prosecution is warranted here," said SoCalGas spokesman Mike Mizrahi. "We will look forward to presenting our evidence to the district attorney through the legal proceedings."
Meanwhile, Mayor Eric Garcetti said the city's Emergency Management Department will open an office in the Porter Ranch area to offer residents such information as potential refunds for city services, updates from the county assessor about possible impacts on tax bills, disaster relief for businesses and access to mental health services.
"Stopping the leak is only the first stage of recovery,'' Garcetti said. "Thousands of lives were upended by this disaster — and the city of Los Angeles is here to help people return to their homes, start doing business again and get back to normal as quickly as possible.''
As of last week, 4,645 households were living in temporary housing at Gas Co. expense. Another 1,726 households have already returned home, according to the utility. The Gas Co. said it also has installed 5,467 air scrubbers at Porter Ranch-area homes and performed "weatherization'' work on 5,410 homes.
LA County health officials said testing and air monitoring will continue in the area.
Residents can get updates on the Aliso Canyon leak, including the return home process, at SoCalGas' website here.
The Associated Press and City News Service contributed to this report.