LOS ANGELES, California, February 22, 2016 (ENS) – A gas well that had been leaking methane at the Southern California Gas Co. (SoCalGas) Aliso Canyon storage facility for nearly four months has been permanently sealed and taken out of service, the California Division of Oil, Gas and Geothermal Resources has confirmed.

The more than 80,000 metric tons of methane released into the atmosphere caused a public health and environmental emergency, and sickened thousands of residents of nearby Porter Ranch, forcing them to relocate.

Aliso Canyon

Southern California Gas Co.’s Aliso Canyon natural gas storage facility leaking methane, Dec. 2015 (Photo by Earthworks)

On October 23, 2015, SoCalGas informed the state officials of a natural gas leak at its Aliso Canyon natural gas storage facility.

On December 4, 2015, SoCalGas began drilling a relief well to stop the natural gas leak by plugging the leaking well at its base.

On February 11, 2016, the company pumped in mud from the relief well and successfully controlled the flow of gas out of the leaking well.

On February 12, SoCalGas began to pump cement from the relief well into the base of the leaking well, completing that process on February 17. State authorities confirmed the seal the next day.

“We are pleased that DOGGR has confirmed that the well has been permanently sealed,” said Dennis Arriola, chairman, president and CEO of SoCalGas. “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.”

“We’ve already started inspecting all of the other wells at Aliso Canyon and will work closely with DOGGR to verify that the wells can be operated safely in the future,” said Arriola.

Continuous measurements are being collected as part of California’s Greenhouse Gas Monitoring network and through other complementary measurements. A revised estimate of the total leak that includes these measurements on theground will take time to process and will not be available until summer 2016.

The leak in well SS25 occurred roughly 500 feet below the surface, and natural gas has been leaking into the ground since the leak started. This residual natural gas will slowly off-gas from the ground and into the atmosphere over the coming weeks and months.

To understand this residual off-gassing, flights to characterize methane emissions will continue for several weeks. Three hours after the well was controlled the emission rate was more than 95 percent less than it was before the well was controlled. Since then, the emission rate dropped by another two-thirds; residual methane is still being emitted but at a decreased rate.

As part of their independent responsibilities, the California Air Resources Board and the South Coast Air Quality Management District have been monitoring on an hourly basis methane levels in the community. Both agencies have reported an abrupt decline of methane levels in the community.

According to the Los Angeles County Department of Public Health, “Mercaptans and other odorants have not been associated with long-term health effects and short-term symptoms will go away once the odor exposure has diminished.”

Now that the well is permanently sealed, there is no longer any gas or odorant being released from the well, the company says. As a result, residents should no longer experience short term health symptoms related to the release of odorants from the gas well.

Noxious fumes have driven residents out of more than 5,000 homes in the nearby community of Porter Ranch and surrounding communities, the utility said.

Residents have complained of headaches, nosebleeds and nausea, which are short-term symptoms associated with the smell of methane.

Residents in Porter Ranch who temporarily relocated and other residents of Porter Ranch and the surrounding communities have been notified that the leak has been sealed and those in short-term housing have now returned home. Residents placed in rental housing will have through the agreed term of their leases to return home.

“We recognize the disruption the gas leak has caused to the residents of Porter Ranch and surrounding communities. We are committed to earning back their trust and confidence over time through our actions, not our words,” said Arriola.

“Now that DOGGR has confirmed that the well is permanently sealed, the operations focus will shift to determining the cause of the leak,” Arriola said. “We will continue to cooperate with state regulators and an independent investigator as they work to determine the cause of the leak.”

SoCalGas has made five pledges in the wake of this disaster.

1 – The company will help residents who chose to relocate to return to their normal lives as seamlessly as possible. This includes quick review and processing of expenses, continued mileage reimbursements to families who enrolled their children in schools outside the Porter Ranch area during the leak, and continued company-reimbursed accommodations for specific special circumstances.

This also includes continuing working with LAUSD and to reimburse it for the reasonable costs that it incurred as a result of the relocation.

2 – SoCalGas will provide dedicated customer service to the impacted residents of the communities surrounding Aliso Canyon through an expanded Community Liaison program and Community Resource Center.

3 – The company will continue to cooperate with regulatory agencies on their investigation into the cause of the leak, and will share publicly available data with the community.

4 – SoCalGas will accelerate the inspection of its other storage wells at Aliso Canyon in compliance with newly issued regulations. In addition, the company will support regulatory policies that adopt best safety practices for all natural gas storage facilities.

5 – The company pledges to develop and implement a plan to mitigate the greenhouse gas impacts of the leak, at company expense, not at the expense of its customers.

Meanwhile, SoCalGas attorneys will be busy defending the company in numerous lawsuits.

California Attorney General Kamala Harris filed a lawsuit against Southern California Gas Company February 2 for violations of California law in connection with the massive methane leak.

Harris’s lawsuit also includes her client, the California Air Resources Board.

The lawsuit alleges that Southern California Gas Company violated state health and safety laws by failing to promptly control the release of the natural gas and report the leak to authorities.

In addition, the lawsuit cites the environmental threat the uncontrolled release of more than 80,000 metric tons of methane into the atmosphere poses to California’s efforts to reduce greenhouse gas emissions and mitigate the pace and effects of climate change.

Harris said, “This gas leak has caused significant damage to the Porter Ranch community as well as our statewide efforts to reduce greenhouse gas emissions and slow the impacts of climate change. My office will continue to lead this cross-jurisdictional enforcement action to ensure justice and relief for Californians and our environment.”

Los Angeles City Attorney Mike Feuer, who filed suit against Southern California Gas Company on December 7, 2015, said, “Attorney General Harris’ action today is a significant step in the ongoing effort to hold Southern California Gas accountable, end this public health emergency and assure it never happens again.”

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