California: Nearly 40,000 residents across Southern California were ordered to evacuate after emergency crews responded to a hazardous chemical threat involving a large storage tank in Orange County.
Authorities issued evacuation orders for residents living in six cities after a tank containing around 7,000 gallons (26,500 litres) of methyl methacrylate began showing signs of failure the previous evening. The chemical is highly flammable and commonly used in plastic manufacturing.
The affected tank is one of three located at the GKN Aerospace facility in Garden Grove, situated roughly 49 kilometres from Los Angeles. The company produces aerospace components for major aviation firms, including Airbus and Boeing.
***Incident Update***
Incident Commander Chief Covey provides an update on the hazardous materials incident in Garden Grove. Our next update will be provided tomorrow morning unless there is a change in incident status. pic.twitter.com/z8xns32iyS
— OCFA (@OCFireAuthority) May 23, 2026
Officials warned that the damaged tank could either rupture and release toxic vapours or explode. Orange County Fire Authority Division Chief Craig Covey explained that a rupture, while dangerous, would allow hazardous materials teams to neutralise the chemical leak and manage the vapour plume. However, he noted that an explosion remained the worst-case scenario.
Emergency crews managed to cool the tank from a safe distance, helping stabilise conditions and providing responders with additional time to contain the situation.
Despite evacuation warnings, Garden Grove Police Chief Amir El-Farra said more than 4,000 residents chose to remain in the affected zone. Garden Grove Mayor Stephanie Klopfenstein urged those still in the area to evacuate immediately, stressing the seriousness of the incident and the potential risks to public safety.
More than a dozen schools were also closed as authorities continued monitoring the situation. Officials said it remains unclear how long the evacuation orders will stay in effect.
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