The gas leak that has been spewing methane in Southern California for the last 16 weeks has finally been plugged, at least temporarily. The well has not been entirely capped – that is expected to take place over the next few days, but the company responsible for the site has announced that they’ve managed to get the flow of gas in check. The mess, however, is far from over, with intense legal battles now expected to ensue as residents who were forced to leave their homes sue the company for damages and authorities fight for environmental compensation.

“We have temporarily controlled the natural gas flow from the leaking well and begun the process of sealing the well and permanently stopping the leak,” said Jimmie Cho, senior vice president of gas operations and system integrity for SoCalGas, the company responsible for the gas well, in a statement. Since the breach in a pipe at the gas storage site at Aliso Canyon on October 23, 2015, an estimated 87,090 tonnes (96,000 tons) of methane have gushed into the atmosphere and surrounding area.

This makes the disaster the largest natural gas leak in U.S. history, equivalent in scale to the Deepwater Horizon oil spill in 2010 – the largest such event in history. Since January, it has been the largest single contributor to climate change in the state of California, and at its peak was emitting a volume of greenhouse gasses equivalent to an extra 7 million cars on the road. While methane doesn’t persist in the atmosphere for as long as carbon dioxide, it is a much more potent greenhouse gas, carrying with it 80 times the warming power over a 20-year period.

“Now comes the critical process of making sure this doesn’t happen again and holding the company accountable,” says Tim O’Connor, the California Oil & Gas Director for the Environmental Defense Fund, which has been monitoring the leak. “SoCalGas can’t respond with its checkbook alone. It has to take care of the neighbors it has harmed and take enough methane out of the air to make up for the damage this leak has caused. This disaster is what happens when aging infrastructure meets lax oversight, and it’s just one example of a problem that is plaguing the oil and gas industry across the country.”

The blowout is thought to have cost SoCalGas around $250 million so far, but that is just taking into account the cost of the capping and the relocation of 6,400 families from the surrounding area. The figure is expected to rise as the lawsuits for health damages, penalties from government agencies, and fines to counter the immense pollution it has caused are taken into account. Once the well has been entirely sealed, residents are expected to be given up to eight days to move back in, before SoCalGas stops paying for their accommodation.

^{Main image: EARTHWORKS/Flickr CC BY 2.0}

^{Gif in text: Aerial footage of the gas leak. Environmental Defense Fund/YouTube}