Many SoCal Gas wells leak, but air quality cops have little recourse

The agency that enforces air quality laws in the Los Angeles Basin has determined that many natural gas storage wells operated by Southern California Gas Company are leaking some amount of methane. 

But inspectors with the South Coast Air Quality Management District currently don't have the authority to cite the company for violating air pollution laws.

The agency can inspect and immediately cite refineries and chemical plants for similar leaks, but longstanding agency rules carved out exceptions for natural gas plants and storage fields, said Mohsen Nozemi, AQMD deputy executive officer for engineering and compliance.

That is because when air pollution rules were put in place decades ago, methane was not seen as contributing to the smog fouling  the L.A. Basin.  In recent years, though methane has been recognized as an air pollutant by the Environmental Protection Agency as well as a greenhouse gas that contributes to climate change, Nozemi said.

It's a gap in the law that could change when the AQMD staff proposes a new set of rules later this year for approval by the agency's governing board.

"When we go out there [to oil refineries and chemical plants] and we find certain leaks, there's an immediate violation notice,"  Nozemi said. "We're trying to find something similar to that for natural gas storage sites as well."

That authority could give the agency the power to order regular inspections and repairs of leaking components at natural gas storage fields and to write immediate violations, creating an incentive for SoCal Gas to find the leaks first, he said.

For now, the AQMD is limited to issuing violations on methane (and the chemical additive mercaptans that gives odorless natural gas its rotten egg smell) when the leak rises to the level of a nuisance. That means the public smells it, complains and the complaint is verified by agency inspectors. AQMD used that rule to cite SoCal Gas with violations during four-month natural gas leak at its Aliso Canyon storage facility. 

Following that leak, AQMD undertook inspections other storage facilities in Valencia, Playa del Rey and Montebello. A number of wells at each facility were found to be leaking some amount of methane.  The results of those inspections were presented Friday to a meeting of the AQMD's governing board.

Nozemi characterized the leaks as minor, but numerous, persistent and recurring.

"We notified the gas company, and they made some attempts to fix them, but every time we go there, we find something else," Nozemi said.

The Honor Rancho gas storage field in Valencia has 46 gas wells and had an average of 3.7 leaking components per well, according to AQMD.

The Playa del Rey gas storage field near LAX had leaks in components on five of every six wells. Previous leaks at that field led to a 2007 settlement between SoCal Gas and the California Public Utilities Commission.  The gas company agreed to additional monitoring for leaks and to operate the field at a lower pressure.

The Montebello underground storage field, which was taken out of service years ago, had the lowest rate of leaking components, about one in five wells. However, inspectors found leaks in about half the closed gas field's isolation valves, which are used to block the flow of gas through the field's network of pipes.

The AQMD inspectors looked at wellheads, flanges, valves and other equipment that is above ground using hand-held vapor analyzers and infrared cameras that can register  images of normally invisible methane. Measuring devices and valves were the most commonly leaking components.

SoCal Gas' massive Aliso Canyon Natural Gas Storage Facility near Porter Ranch sustained the nation's largest-ever methane leak, and it was finally plugged in mid-February. AQMD inspectors have found leaks in well components there over the past few months, but that storage field did not receive the same all-at-one-time inspection as the other three gas fields, so an analysis of its leaking gas well components was not provided to the AQMD board.

Officials with SoCal Gas did not immediately respond to questions about the findings of leaks at the three gas fields.

In an emailed statement about the leaks, Earthjustice Attorney Adrian Martinez said, “I’m deeply troubled by today’s discussion. We need proper oversight of Los Angeles' large gas storage fields because the old equipment at these sites will continue to have leaks. I urge our air district to take a much more active role to protect the public from this dangerous pollution.”