Tens of thousands of people in Southern California were ordered to evacuate after officials warned a storage tank at an aerospace facility was likely to fail and could either rupture and spill its contents or explode. The tank at GKN Aerospace in Garden Grove, about 38 miles south of Los Angeles, holds roughly 7,000 gallons of methyl methacrylate, a highly volatile, flammable chemical used in plastic production, Orange County Fire Authority Chief Craig Covey said.
Methyl methacrylate is capable of self-heating and, if released, can ignite from a small spark or flash, potentially triggering an uncontrolled fire or explosion, said Elias Picazo, an associate chemistry professor at the University of Southern California. Fire crews have been focusing on cooling the tank to slow or prevent failure.
Officials described two main dangers: a catastrophic spill that would release thousands of gallons of hazardous material onto the facility grounds, or an explosion that could send vapors and particles into the air and damage nearby tanks that store other chemicals and fuel. Because methyl methacrylate vapors are heavier than air, they can settle and collect near ground level; crews have constructed sandbag containment barriers to keep any spilled material from entering storm drains or nearby waterways.
So far there have been no reported injuries or deaths. Authorities say no airborne particles that would threaten public health have been detected and there is no active plume, but people within a one-mile radius were evacuated and the broader area recommended that residents shelter indoors. There is no timeline for when evacuation orders might be lifted.
Health officials note that exposure to methyl methacrylate can irritate the eyes, skin and respiratory system and may cause nausea or dizziness. Local and federal teams are investigating the cause of the leak while continuing mitigation efforts, including cooling and containment, and evaluating additional options to bring the situation to a safe conclusion.
Orange County officials described the incident as among the most dangerous they have faced in recent years and urged the public to follow evacuation and shelter-in-place orders until authorities declare the area safe. The response remains active and evolving as crews monitor the tank and surrounding hazards.