The chemical safety board's annual budget is about $12 million. It's among a number of independent agencies the president is looking to kill. "The budget eliminates hundreds of programs and focuses funding to redefine the proper role of the federal government," Trump's budget blueprint states.
DeSaulnier was among a number of federal legislators who pressured former CSB chairman Rafael Moure-Eraso to resign in 2015 amid management problems at the agency. Since then, DeSaulnier said, the board had made significant strides.
House Democrats and Republicans will work to save the agency, he said.
If they don't, the region will be in trouble, according to Contra Costa County's chief environmental health and hazardous materials officer, Randy Sawyer.
"If Congress approves the defunding of the Chemical Safety Board, the public and the workers at the refining and chemical facilities will lose," said Sawyer, whose office audits local refineries and responds to facility malfunctions, in an email. "I also believe the chemical industry will be the biggest loser."
The industry group that represents oil refineries in California is taking a wait-and-see approach to the president's proposal.
"These are issues that we are monitoring closely," said Catherine Reheis-Boyd, president of the Western States Petroleum Association in an emailed statement. "Our member companies believe in transparency and operate in an environment that is highly regulated by federal, state and local agencies."
When asked for reaction to the proposal, a Chevron spokesman deferred to the American Petroleum Institute, which has yet to respond to requests for comment.
But a Tesoro official rejected the idea of eliminating the board.
"The industry does not support the abolition of the agency," Stephen Brown, vice president of federal affairs at the company, told Bloomberg.
If the chemical board goes away, local and state regulators will have to fill a void in regulation, according to Contra Costa Supervisor John Gioia, who represents the area of Chevron's Richmond refinery.
"We will step up our own investigations if the U.S. Chemical Safety Board is not around," Gioia said in an interview Friday. "It will mean greater resources spent by local and state agencies to replace the work that the board has done."
The critique from environmentalists is more harsh.
"The Chemical Safety Board saves lives and holds dangerous facilities accountable," said Maya Golden-Krasner, a senior attorney at the Center for Biological Diversity.
"Millions of Californians live near refineries where life-threatening explosions and chemical releases are not uncommon," Golden-Krasner said. "Without the board's oversight, the root causes and full extent of accidents that we've seen at Chevron and other refineries most likely would never be known."