SAN FRANCISCO >> Gov. Jerry Brown’s sister is a paid board member of the company that owns a natural-gas well whose leak is forcing thousands from their Southern California homes, and a watchdog group and the governor’s aides disagree over whether that makes a conflict of interest for the governor.

Southern California Gas Co., a subsidiary of San Diego-based Sempra Energy, owns a gas well that has been spewing an estimated 1,200 tons of methane, along with other gases, daily since at least late October. On Friday, the governor wrote Southern California Gas to note that the utility’s efforts to stop the leak had been insufficient, to defend the state’s handling of the problem, and to say that he had directed state agencies to work with the California attorney general in investigating the causes of the leak, according to a copy of the letter released by the governor’s office.

The massive leak amounts to about a quarter of the state’s total output of climate-changing methane. The site is believed to be the largest underground natural-gas storage facility in the West and can hold enough natural gas to fuel Southern California for a month.

While public-health officials say the leak is not an immediate health threat, residents complain of nosebleeds, headaches and nausea.

The utility is paying to relocate nearly 3,000 households. Los Angeles County and the Los Angeles school board have declared the crisis a state of emergency, with the school board deciding Thursday to move students out of two schools at the affected Porter Ranch neighborhood.

Local residents and environmental activists responded to the news Saturday by saying that the Public Accountability Initiative report suggests that the governor puts family ties to oil and gas before the welfare of all Californians.

They reinstated the call upon Brown to step in personally and declare a state of emergency for the affected residents around Porter Ranch.

“While we are enthused the Governor seems to be aware of the Porter Ranch Gas Leak, we are scratching our heads trying to figure out where he’s been,” said Matt Pakucko, president of Save Porter Ranch, a San Fernando Valley-based advocacy group, in a statement. “Eight weeks into a crisis that has relocated thousands of our neighbors and disrupted our community, and Jerry Brown still won’t acknowledge his constituents.

“He continues to ignore us while this gas leak unravels his reputation as a so-called climate leader.”

He said Porter Ranch residents stand with Los Angeles County and Councilman Mitch Englander in their demand that the Governor declare a state of emergency.

He added that the Aliso Canyon Storage Facility is too old and dangerous, and the regulatory apparatus too dysfunctional, for Southern California Gas Co to continue operating it, and demanded its immediate closure.

“Governor Brown’s silence on the Porter Ranch gas leak is immoral and egregious given his conflict of interest and close ties to Sempra,” said Alexandra Nagy, a spokeswoman for Food & Water Watch, an environmental group based in Los Angeles. “A real climate leader wouldn’t let family ties get in the way of protecting Californians from a massive public health and climate disaster.”

Both said Brown needs to stand up for the community by declaring a state of Emergency and work to shut down the Aliso Canyon gas storage field.

Brown’s sister, Kathleen L. Brown, a lawyer and a former California state treasurer in the 1990s, has served as a director of Sempra Energy since 2013, receiving $188,380 in salary last year. Federal filings show she also holds stock in the company currently worth about $400,000.

A New York-based citizens’ oversight group, Public Accountability Initiative, raised the issue this week, faulting the governor for not publicly addressing his sister’s role with the company in the gas leak.

“It is a conflict of interest and it’s a conflict of interest that needs to be managed transparently and openly,” said Kevin Connor, the group’s director.

Brown spokesman Evan Westrup said there was “absolutely not” any conflict of interest that could potentially affect the state’s management of the crisis.

“The state is exercising its full regulatory and oversight authority,” Westrup said. “The focus is the health and safety of residents, period.”

Sempra spokesman Art Larson also said the company saw no conflict. Larson declined to say whether Kathleen Brown’s role on the board, and on the board’s environmental committee, involved her directly in decision-making or interacting with the state in managing the leak. Brown’s sister did not immediately respond to a message seeking comment left at her San Diego law firm.

In 2010, Kathleen Brown left a West Coast position with Goldman Sachs in part to avoid any perception of conflict of interest after her brother was elected governor, the securities firm said then.

Mark Toney, the head of The Utility Reform Network, a San Francisco-based citizens’ group monitoring state regulation of utilities called the Porter Ranch gas leak “a major environmental disaster” that should be getting more attention all around.

Toney said the focus should be stopping the leak — something that authorities say will likely take months — and then investigating to fully determine responsibility. “This is the kind of accident that should never happen,” he said.

Staff writer Dana Bartholomew and Associated Press writer Ellen Knickmeyer contributed to this report.