California Gov. Gavin Newsom affirmed the need to decommission the Aliso Canyon Natural Gas Facility, which caused thousands of families to evacuate their homes in 2015 due to the largest known methane leak in the country, after regulators on Thursday voted to delay the closure.

“Aliso Canyon must be closed for good, but without harming working families with skyrocketing utility bills,” Newsom said of the underground gas storage facility located in the Santa Susana Mountains, about 28 miles north of Los Angeles.

“Reducing reliance on the facility has gone slower than I would like, but the Public Utilities Commission—a constitutionally independent agency—has set out a reasonable path that protects residents near the facility and doesn’t throw the natural gas market into chaos.”

The regulators had opted to gradually reduce the Southern California region’s reliance on the facility.

The California Public Utilities Commission voted 4–0 in favor of a judge’s proposal to keep Aliso Canyon open at this time. One commissioner recused themselves from the vote.

In October 2015, Aliso Canyon’s natural gas storage wells failed and 120,000 metric tons of methane and other gases poured into the atmosphere above the San Fernando Valley, causing residents to get ill with headaches, vomiting, nausea, and nosebleeds. Southern California Gas Co., the company that operates Aliso Canyon, capped the 60-year-old well after 118 days.

State regulators said the gas company didn’t properly assess its aging wells for disaster potentials and claimed the facility wasn’t prepared to handle a leak of this magnitude.

Aliso Canyon is the state’s largest field of natural gas and one of the largest in the country. It was built in the 1950’s to pump oil from under the Santa Susana Mountains. The well, however, was mostly depleted by the 1970s. It was then converted into a natural gas storage field with 86 billion cubic feet of storage capacity. When the leak occurred, it was filled almost to capacity. Forty-eight of the site’s 116 wells are over 60 years old.

In a statement released last week, Newsom assured the surrounding communities that, despite motions to keep Aliso Canyon operational, their safety was the top priority. He also said that the state is working with local and federal state partners to ensure the facility is safe with new protocols and rigorous testing. Newsom also reiterated the state’s commitment to reducing its dependency on fossil fuels and moving toward clean and renewable energy.

“We’ve done more than any administration in history. But there’s more work to do, including closing Aliso Canyon once and for all,” the governor stated.

Commissioners said Thursday’s vote would allow regulators to move toward a practical phasing out of Aliso Canyon, which remains the region’s main source of energy.

“This decision puts forward a path to the closure of Aliso Canyon that is achievable, realistic, and protective of families and businesses who are struggling to pay energy bills,” CPUC President Alice Reynolds said in a statement. “Huge progress is underway to bring online clean energy resources and drive down demand for natural gas-fired power plants.”

The Associated Press contributed to this report.