California Gov. Jerry Brown declared a state of emergency in California Wednesday and ordered “all necessary and viable actions” to plug the leakage of methane gas from an underground storage facility. The leak, which began in October when an injection well pipe ruptured, has forced thousands of residents to evacuate from the region after they reported feeling ill.

“The California Public Utilities Commission is investigating the gas leak to determine its cause and any possible violations and is collecting information about the costs of responding to and fixing the leak,” the governor said, in a statement released Wednesday, adding that he had acted based on requests from the residents of Porter Ranch — located on the outskirts of Los Angeles — and after taking into account “the prolonged and continuing duration” of the gas leak.

“The Governor’s Office of Emergency Services ... shall provide frequent and timely updates to residents affected by the natural gas leak and the appropriate local officials, including convening community meetings,” Brown added, in the statement.

The underground well, owned by Southern California Gas Company (SoCal), has been spewing an estimated 1,200 tons of methane — a potent greenhouse gas — daily. According to a real-time counter created by the advocacy group Environmental Defense Fund, the rupture has so far released over 79,000 tons of methane, making it California’s single-largest contributor to climate change.

Although the well is situated in a mountainous area more than a mile away from residential areas, residents have complained of health effects like headaches, nausea, vomiting and breathing difficulties.

Pressure has been mounting on state authorities and the company to intensify efforts to stop the leak. However, SoCal, which has begun providing temporary accommodations to displaced residents, reportedly says that the leak may not be plugged before the end of March.

“In terms of timelines this is going to surpass the gulf oil problem by a mile,” Tim O'Connor, a lawyer with the Environmental Defense Fund, told the BBC. “What we do know is that that climate equivalent of this leak is like burning thus far almost 700 million gallons of gasoline or it's the same amount of pollution as 4.5 million cars put out every day.”