On Tuesday evening, Southern California’s air quality regulator sued SoCal Gas, the company that owns a leaking natural gas storage well just north of Los Angeles. The leaking well has been venting hundreds of thousands of pounds of methane per hour into the atmosphere for the last three months.

Further Reading Regulators halt plans to capture and burn leaked methane in Southern California

The civil lawsuit demands damages (PDF) from SoCal Gas for creating a nuisance for the residents of the nearby Porter Ranch community and for negligently operating the Aliso Canyon storage facility that houses 115 storage wells, including the leaking SS-25 well. The South Coast Air Quality Management District (SCAQMD) is asking for up to $440,000 per day that the leak continues, based on six alleged violations.

The leak began on October 23, and after several failed attempts to plug it, SoCal Gas began drilling a relief well down to the 8,500-foot-deep reservoir where the natural gas is stored. (The reservoir is just one of many cavities that once held oil and were sucked dry decades ago. SoCal Gas repurposed these reservoirs in the 1970s to store natural gas.) In the meantime, the gas has been venting into the atmosphere.

Natural gas is primarily made of highly flammable methane that is treated with chemicals to create a strong rotten-eggs odor so humans can identify a leak. While the methane itself has little effect on the immediate health of the humans living in nearby Porter Ranch, the chemicals that the gas has been treated with are causing headaches, nausea, and bloody noses. The City of Los Angeles has ordered SoCal Gas to relocate any Porter Ranch families that request temporary housing. "As the result of the odors and adverse health effects caused by the natural gas leak from Well SS-25, thousands of people living in the communities near the Facility have been forced to leave their homes, local schools have been closed, and thousands of students have been relocated,” the complaint against SoCal Gas alleges.

SCAQMD says that it has received about 2,000 complaints about the smell coming from the Aliso Canyon facility since the leak began. As of last week, SoCal Gas had found temporary housing for 3,112 households, from short-term lease apartments and houses to hotel rooms. According to the Los Angeles Times, however, last week SoCal Gas began quietly telling Porter Ranch residents that it was too difficult and expensive to find any more temporary housing. The Los Angeles City Attorney threatened legal action against the company, and it reversed its decision to stop offering housing. In one case, SoCal Gas offered a family of seven people and three dogs a single hotel room.

In addition, the methane leak might not cause an immediate health risk to humans, but its long-term ramifications are very serious. Methane is a highly potent greenhouse gas—more potent in the short-term than CO 2 —and the California Air Resources Board estimated in November that the leak had released the equivalent of one-quarter of California’s total methane emissions.

In the complaint filed Tuesday at Los Angeles Superior Court, SCAQMD wrote:

In addition to harming persons living, working, and attending school in the communities near the Facility, SoCalGas' leak has contributed to global warming by emitting billions of cubic feet of methane into the atmosphere. Methane is a greenhouse gas, which warms the earth by absorbing heat energy from the sun and slowing the rate at which heat energy escapes. The United States Environmental Protection Agency has developed a standard to compare the global warming impacts of different greenhouse gases. The standard is called the Global Warming Potential. The Global Warming Potential of carbon dioxide (C02), which is the most common greenhouse gas, is 1. The United States Environmental Protection Agency estimates that the Global Warming Potential for methane is between 28 and 36 over a 100-year period. Global warming has caused significant harm to animals, plants, and people around the globe and poses the risk of greater harm in the future. SoCalGas' methane leak from Well SS-25 has increased the risk of harm in the future from global warming.

According to yesterday’s complaint, the leak is releasing natural gas at a rate of approximately 127,868 pounds per hour.

SCAQMD went on to say that the cause of all this trouble is SoCal Gas’ operational negligence, from the design to the inspections of the well. It also said that SoCal Gas was too slow in responding to the leak when it was first discovered, and the air quality regulator accused the gas company of failing to correctly hire and vet contractors to manage the well before and after the leak. "SoCal gas knew of the emission,” SCAQMD wrote, "and SoCalGas failed to take corrective action within a reasonable period of time under the circumstances.”

The Air Quality Management District has held several meetings in recent weeks about the impact of the leak, and it recently stopped a plan to capture and burn off the venting methane after utility regulators raised a concern that the instability of the well and the flammability of the methane could cause a blowout of the wellhead or a deadly explosion. Currently, SoCal Gas forbids smartphones or even watches at the leak site for fear of a spark setting off an explosion.

According to the Los Angeles Times, SCAQMD approved an abatement order just days ago, which requires SoCal Gas to shut down the damaged well permanently, establish a leak detection system, and fund an independent study on the health effects of the leak.

Environmentalists and community activists, however, are pushing to get regulators to make SoCal Gas shut down the entire facility, which is the largest natural gas storage facility west of the Mississippi River. The facility stores up to 160 billion cubic feet of gas, which the gas company injects in the summer when gas isn’t in high demand and reclaims in the winter when demand is higher.

Ars contacted SoCal Gas but did not receive a response. The company told the Los Angeles Times last night that it would "not comment on pending litigation."

On Monday, the Governor's Office of Emergency Services (OES) reported that SoCal Gas' relief well has now reached a depth of 8,400 feet, "approximately 200 feet away from where it is intended to intercept the leaking well."

"Once drilling reaches the leaking well's base, crews will transition from drilling operations to pumping heavy fluids, cement, and drilling mud into the target well to stop the flow of gas," the OES wrote. "Enough cement will be inserted to displace the fluids/mud and leave an initial seal of cement that will effectively cut off the leaking well."

The well is expected to be sealed off by late February.