50,000 Californians Still Evacuated as Cracked Chemical Tank Hangs Over Orange County

GARDEN GROVE, CA — Fifty thousand people remained under evacuation orders Sunday night with no clear timeline for return, as emergency crews conducted an all-night operation to determine whether a cracked chemical storage tank at an aerospace plant in Orange County had finally stopped building pressure — or was still on its way to blowing.
The tank in question holds roughly 7,000 gallons of methyl methacrylate, a highly volatile industrial chemical used in plastics and resin manufacturing, at GKN Aerospace’s facility on Western Avenue in Garden Grove. The incident started Thursday afternoon, when the company’s automatic sprinkler system activated after internal temperatures in the tank began climbing past safe thresholds. What firefighters found when they arrived was a tank already approaching a condition they did not have a clean way to fix.
“This is as real as it gets,” Orange County Fire Authority Division Chief Craig Covey told reporters Saturday. “It’s the worst-case scenario I’ve ever faced in my career.” Covey laid out the math plainly: the tank either fails and spills thousands of gallons of toxic chemicals across the parking lot and surrounding area, or it goes into thermal runaway and detonates, triggering secondary explosions from other fuel and chemical storage nearby.
By Sunday, a third option was being explored. Drone-mounted infrared equipment confirmed a crack in the tank’s exterior, but OCFA Interim Chief TJ McGovern said atmospheric monitoring showed no chemicals currently leaking. He described overnight reconnaissance as yielding “positive intel” and said an update would follow Monday morning. A class-action lawsuit against GKN Aerospace was filed Sunday by two law firms on behalf of displaced residents.
Governor Newsom declared a state of emergency for Orange County on Saturday. The Orange County District Attorney launched a probe into what caused the incident. Evacuation centers in Garden Grove, Cypress, Stanton, Fountain Valley, Anaheim, and Buena Park filled quickly — some reaching capacity. More than a dozen schools remain closed indefinitely.
Five miles away, Disneyland confirmed it is monitoring the situation but remains open and outside the evacuation zone. That detail tells you something about the scale of the perimeter authorities drew.
GKN Aerospace, a manufacturer of components for commercial and military aircraft, issued a statement saying it is “working round the clock to mitigate the risk of a leak” and apologized for the disruption. The company has not publicly explained what caused the original temperature spike.
Methyl methacrylate releases energy exothermically when it reacts. In a sealed container under heat, that reaction creates pressure that can turn the tank itself into a projectile. For three straight days, emergency teams have been cooling the exterior with water while engineers assess whether the chemistry inside has stabilized. As of Sunday night, they did not have a definitive answer.
The people who live within a mile of Western Avenue are sleeping somewhere else. They have been for four days.