40,000 Evacuate in Orange County Over Risk of Toxic Chemical Tank Explosion

More than 40,000 residents across multiple Southern California cities have been ordered to evacuate due to fears that a tank containing a toxic chemical at an aerospace manufacturing facility in Garden Grove may explode. Authorities announced the evacuation Friday after officials warned that the compromised tank is likely to fail.

The tank, located at the GKN Aerospace site on Western Avenue, holds an estimated 6,000 to 7,000 gallons of methyl methacrylate, a highly flammable and volatile chemical used in plastics production. Orange County Fire Authority (OCFA) incident commander Craig Covey said, “This thing is gonna fail. We don’t know when,” underscoring the urgency of the situation.

Initial evacuation orders were issued Thursday following a vapor release at the facility, but were briefly lifted after firefighters cooled the tanks. However, on Friday, the valve controlling the tank became inoperable, prompting renewed and expanded evacuation orders covering parts of Garden Grove, Cypress, Stanton, Anaheim, Buena Park, and Westminster.

“There are literally two options left remaining: One, the tank fails and spills a total of about 6,000 to 7,000 gallons of very bad chemicals into the parking lot and that area,” Covey explained. “Or two, the tank goes into a thermal runaway and blows up, affecting the tanks that are around it that have fuel or chemicals in them as well.”

Despite the risk, officials reported no active gas leak or harmful air particulates at the time of the briefing. “Right now, there is no active gas leak coming off that thing,” Covey said. The tank is being cooled by a sprinkler system and an unmanned hose line to prevent temperature increases.

Health officials described methyl methacrylate as a respiratory irritant that can cause lung, skin, and eye irritation, as well as nausea and dizziness. The U.S. Environmental Protection Agency notes that exposure may lead to headaches, coughing, wheezing, and has been suggested as a possible cause of colon and rectal cancers, though this is unproven. The chemical is heavier than air, meaning its vapor tends to settle and sink.

Dr. Regina Chinsio-Kwong, a local health official, called the emergency unprecedented and difficult to predict. “This is a unique situation,” she said. “We don’t have information of a similar situation where this happened, right? So we’re going into unique times, and we have limited information.”

Authorities have assembled a team including state and national experts to explore ways to depressurize the tank and mitigate exposure. OCFA is leading the emergency response with support from the EPA, which is conducting air monitoring. Drones are also being used to monitor the tank’s temperature.

No injuries have been reported. The cause of the leak remains under investigation.

Residents are advised to stay indoors and follow evacuation orders. Evacuation centers have been established at the Garden Grove Sports & Recreation Center and the Cypress Community Center. For information, residents can contact the Garden Grove 24-hour call center at (714) 741-5444 or the Orange County public information hotline at (714) 628-7085.

GKN Aerospace stated in an email, “The situation at our Garden Grove site remains ongoing, and we are fully focused on working with emergency services and the relevant authorities to ensure the safety of our employees and the local community.”