A chemical tank at a Garden Grove aerospace plant came close to exploding over a six-day emergency that forced more than 50,000 residents from their homes and raised new questions about whether California’s regulatory system missed warning signs.
The crisis unfolded at GKN Aerospace, a facility in Orange County that produces cockpit windows and shields for military aircraft. As the tank overheated, officials feared it could rupture and release a toxic chemical cloud over surrounding neighborhoods. A failed cooling-system valve complicated the response, and crews used drones to check the tank’s temperature from outside the danger zone. Emergency teams also deployed an unmanned ground monitor — a portable water cannon — to spray the side of the tank in an effort to cool it.
At the height of the emergency, Gov. Gavin Newsom’s office sent more than 700 people to Garden Grove to assist with the response. The danger eased only after the tank cracked enough to relieve pressure without triggering a chemical explosion. Evacuation orders were lifted by Tuesday night, but the incident left residents, advocates and regulators searching for answers.
The near-catastrophe exposed gaps in several layers of oversight that state and local agencies have not fully addressed. Air quality regulators had flagged compliance problems at the facility years before the emergency. The Orange County District Attorney’s Office is now investigating whether the company violated any laws. Community advocates and chemical safety experts say residents deserve a clearer accounting of what regulators knew, what safeguards were in place and why the tank came so close to failing.
GKN had been working to resolve environmental compliance notices as regulators and local planners considered an expansion of the plant that would increase its capacity to manufacture parts for F-35 military fighter jets.
The South Coast Air Quality Management District inspected GKN three times over the past decade. For much of that period, the facility was classified as a “minor source” of emissions under the district’s permitting program, meaning regulators were not required to inspect it frequently.
That limited oversight may have contributed to what records show became a years-long compliance problem. Regulators said those violations were not tied to the storage tank involved in the emergency, which contained methyl methacrylate.
In 2020, GKN voluntarily reported certain issues that prompted South Coast air quality regulators to inspect the facility and review its records. The district’s investigation found the company had failed to follow multiple rules dating back to 2017. According to regulatory reports, the plant, located less than a mile from homes and schools, had not maintained required emissions records, had operated new equipment without proper permits and had used equipment that did not match descriptions in its existing permits.
The air district did not issue a formal notice of violation until April 2021. A settlement was not signed until late 2024, when GKN agreed to pay more than $900,000. The company did not admit liability, and the agreement resolved 14 alleged violations.
The South Coast district now classifies GKN as a “major source” of emissions, a designation that brings annual inspections. A district spokesperson said the company has applied for a more comprehensive permit at regulators’ direction.
For residents and community advocates, the timeline has deepened frustration.
“That delay and the fact that GKN has operated practically with impunity has caused tens of thousands of Garden Grove residents to pay the price,” said Tracy La, executive director of VietRISE, a nonprofit that supports Vietnamese and immigrant communities in Orange County.
La said evacuees faced costs for temporary housing, medication replacements, transportation and other expenses after being forced from their homes.
“It is frustrating that regular people constantly have to bear the burden when government officials are unwilling to hold powerful, wealthy corporations accountable,” she said.
Garden Grove is part of Little Saigon, home to one of the largest Vietnamese American communities in the country, including many immigrants and refugees from the Vietnam War.
Some residents know methyl methacrylate not as an aerospace chemical, but as a workplace hazard. Lisa Fu, executive director of the California Healthy Nail Salon Collaborative, said Vietnamese nail salon workers have fought for years to remove the chemical from their workplaces because of concerns about its effects on workers’ lungs, skin and eyes.
California banned methyl methacrylate in nail salons and cosmetology schools in 2015 after workers raised health concerns. Now, Fu said, the same chemical was leaking from a tank only a few miles from Little Saigon. She said members of her organization and neighbors reported bloody noses, itching and the deaths of pet birds.
Air monitors set up by the U.S. Environmental Protection Agency and the South Coast air district around the plant recorded pollution levels within normal ranges. But Fu said the gap between official readings and residents’ experiences has contributed to mistrust of regulators.
“At press conferences, you hear that there are no fumes, no vapors, no leaks, no pollution,” Fu said. “They say it is safe. Safe for whom? We believe the community when the stories keep coming in.”
Community advocates are calling on Garden Grove leaders to shut down the facility and adopt a moratorium on military manufacturing facilities and expansions in the city.
GKN’s broader permit application remains under review by the South Coast air district, and the public is expected to have an opportunity to comment. A district spokesperson said the agency had aimed to release the permit for public comment before the end of the year, though the timing could change because of the emergency.
The incident has also raised concerns about a possible gap in chemical safety rules. Methyl methacrylate is a volatile compound widely used in plastic manufacturing. Officials feared that as the liquid overheated, the tank could rupture and spill thousands of gallons of chemicals or explode.
“It’s like a soda can you left in the car in the middle of summer,” said Andrew J. Whelton, a professor of environmental engineering at Purdue University. “The pressure that builds up inside the can exceeds what the metal can handle.”
When the tank began overheating, it triggered a chemical reaction that responders could not stop. Craig Covey, a division chief with the Orange County Fire Authority, said during a May 22 news conference that the reaction had clogged valves crews needed to inject a neutralizing agent.
Despite the danger, methyl methacrylate is not regulated under the U.S. Environmental Protection Agency’s Risk Management Program or California’s parallel system, known as CalARP. That means the tank may have been governed by a lower-level hazardous materials program, limiting the tools available to regulators for overseeing how it was stored.
“If you live there, if you’re a neighbor, can you go and see what chemicals they have stored on site?” asked Jane Williams, executive director of California Communities Against Toxics. “No, you can’t.”
The federal program has not added reactive chemicals to its list of covered substances, despite recommendations from the U.S. Chemical Safety Board, which investigates chemical accidents. The Trump administration has proposed eliminating funding for the Chemical Safety Board after October and rolling back 2024 Risk Management Program amendments that had begun expanding chemical safety requirements.
A similar gap exists in California. The California Environmental Protection Agency confirmed that methyl methacrylate is not regulated under the state’s accidental release prevention program.
Orange County health officials said GKN had a hazardous materials business plan, a lower-tier document that lists chemicals stored at a facility, but did not have a risk management plan. The county said CalARP does not apply to the plant because methyl methacrylate is not on the program’s list of regulated chemicals.
CalMatters also asked the California Division of Occupational Safety and Health whether workplace safety rules for high-risk industrial processes applied to the facility, which could have made it subject to accidental release oversight through another process. The facility had undergone multiple occupational safety and health inspections before the tank emergency. Cal/OSHA did not respond to that question before publication.
Williams said chemicals that fall outside federal and state accident prevention programs may also be left out of community emergency planning and drills. That can mean nearby residents do not fully understand the risks they face or how authorities would respond.
GKN did not respond to written questions before deadline. In recent days, the company has thanked the community and emergency responders.
“We recognize that there is still much work to be done,” said Steve Carlin, a senior vice president at GKN who oversees programs at the Garden Grove plant.
Angela Johnson Meszaros, an attorney with the environmental group Earthjustice, said people living near companies such as GKN have reason to believe someone is enforcing safety rules.
When an incident like this occurs, she said, residents are angry because they wonder, “Wait, nobody was paying attention to this and now I’m sleeping on the sidewalk?”
She said the regulatory system is aimed at bringing facilities into compliance, rather than ensuring they are operating safely.
“We have a system built around the idea of getting facilities to comply with regulations,” Johnson Meszaros said. “But we need a system that ensures they operate safely, and some facilities may not have a culture that allows us to trust them with our lives.”
It remains unclear whether any single agency will produce a comprehensive report explaining what went wrong.
The Orange County District Attorney’s Office has opened a criminal investigation, spokesperson Kimberly Edds confirmed. Prosecutors sent letters to GKN ordering the company not to destroy or alter evidence.
Through an anonymous tip line, the office is seeking information about the chemical release, facility operations and maintenance of the tanks and related systems.
California law makes it a crime to knowingly or negligently handle or store hazardous waste in a way that creates an unreasonable risk of fire, explosion, serious injury or death. Edds declined to specify which parts of the law investigators are examining.
In a similar 2024 case, Alameda County prosecutors charged a scrap metal company after a fire revealed years of hazardous materials violations. Prosecutors later said they could not prove the case beyond a reasonable doubt and dropped it.
On the regulatory side, no one agency is responsible for producing a complete account of the Garden Grove incident. Instead, each agency involved in the emergency will prepare its own findings, which will be released according to its own policies and timelines, said Brian Yau, a spokesperson for the Orange County Fire Authority.
Yau said hazardous materials officials, air quality regulators, environmental officials and the company were developing a cleanup plan. On Friday, the Fire Authority transferred oversight of cleanup and remediation to the county health agency, fire spokesperson Greg Barta said.
Asked whether he was concerned about industrial facilities operating near densely populated residential areas, Newsom praised local and state emergency responders and said the state is reviewing the facility’s safety history. He also acknowledged the limits of state action in built-out urban areas.
“When it comes to industrial facilities located in and around urban centers,” Newsom said at a Thursday news conference, “that is a more complicated geographic question.”
State Sen. Tom Umberg, a Santa Ana Democrat, said new legislation will be proposed in response to the narrowly avoided disaster.
Williams, of California Communities Against Toxics, said the incident should lead to a broader review of California’s rules for hazardous industrial sites, not only at GKN but at all facilities storing chemicals that fall outside the state’s strictest oversight programs.
“Everyone wants to get back to normal as quickly as possible, because our nerves are frayed, and the way to calm ourselves is to go home, sit on the couch and hug our cat,” Williams said. “But in a situation like this, where such a serious incident occurred, it is critical to make sure the safety systems that failed are not the only ones at risk.”
Original source: CalMatters
