LOS ANGELES -- A blowout at a natural gas well that spewed massive amounts of climate-changing methane for nearly four months and drove thousands of Los Angeles families from their homes has been permanently sealed, state officials declared Thursday.
The announcement certifying that the ruptured well had been plugged with cement brought a point of closure in the long-running drama that has disrupted life in the Porter Ranch community and drawn attention to a massive underground storage facility owned by Southern California Gas Co.
Testing showed the well was no longer leaking, Jason Marshall, chief deputy director of the California Department of Conservation, said at a news conference.
"Gas emissions are controlled and air quality has returned to normal levels," Marshall said.
Families in short-term housing -- at hotels or staying with friends and relatives -- will have eight days to return before the gas company stops reimbursements. Those who rented apartments and houses can stay through their leases as late as April 30.
Investigations now will begin into how the well had managed to blowout and leak uncontrollably for so long. It was drilled for oil in 1953 and reused for natural gas storage in the 1970s.
Wells of the same vintage will undergo rigorous inspections and all 114 wells near Porter Ranch must pass muster with the state before gas can be injected in the field -- a process that could take up to 20 days per well, Marshall said.
Other state agencies are looking into how to replace the energy the facility is capable of providing and what would happen to energy supplies if the Aliso Canyon facility -- the largest in the West for gas storage -- does not reopen.
Some residents angry or sickened by the leak want to see the storage area permanently closed. The leak was reported in October, and nearby residents complained of headaches, nausea, dizziness and nosebleeds.
Residents were relieved by the state's declaration, but some expressed concerns about a repeat blowout or air pollution from the long-lasting leak.
Simrat Aujla said she hadn't noticed the sulfurous stench in recent days but remained concerned about whether the air was clean. She hadn't resumed walking in her partly vacant gated Porter Ranch community.
Uriel Rosoff of neighboring Chatsworth said his adult daughter had to move out of his house because of nosebleeds, respiratory problems and migraine headaches. He wanted to be assured that safety valves were in place on wells in the mountain top facility, especially since the leaking well had a safety valve removed in 1979 that was not replaced.
"I don't know what to believe," Rosoff said. "I'm skeptical of the other 114 wells up there that have been there anywhere from 30 to 70 years."
The gas company, a division of Sempra Energy, said it expects expenses of as much as $300 million for temporarily lodging 6,400 households, plugging the leak and the loss of gas that gushed for 16 weeks.
The figure does not include potential damages from at least 67 lawsuits, penalties from government agencies and expenses to mitigate pollution, which the company noted could be significant.
Dennis Arriola, president and chief executive of SoCalGas, said thye day marked a turning point and he pledged to take several steps to help residents return and push for new regulations to make gas storage safer.
"I want to tell you that I recognize the disruption that this gas leak has caused to your lives," Arriola said. "The discomfort of those who have experienced symptoms related to the odor agent in the gas; the challenges experienced by your families that have had to move or switch schools with their kids."
Natural gas is odorless and invisible, but an additive used to make it detectable to the human nose blanketed neighborhoods at times with a nauseating stench.
Public health officials blamed the odorant for many of the symptoms residents complained about, though they said they don't expect long-term illnesses from the gas, which is mostly methane, or trace elements such as cancer-causing benzene.
Air quality monitors set up during the leak will remain in place to make sure the air is clean to breathe.
Although the well has been declared sealed, Gov. Jerry Brown won't immediately lift an emergency declaration he made last month.