Authorities in Orange County, California, have ordered about 40,000 residents to evacuate due to fears that a tank containing the chemical methyl methacrylate could leak or explode. The tank, located at a GKN Aerospace facility in Garden Grove, has been overheating, prompting emergency teams to work for two days to prevent an explosion. The evacuation order covers a nine-square-mile area surrounding the site.

The incident began on Thursday, May 21, when gas started leaking from the tank filled with the highly flammable chemical used in resin and plastic production. Initially, a hazardous materials team directed residents to leave, later lifting the order when the situation seemed under control. However, a damaged valve worsened the risk, leading local authorities to reissue the evacuation directive.

Officials warned that the tank could rupture, releasing 6,000 to 7,000 gallons of toxic material, or explode due to rising temperatures, potentially igniting nearby fuel and chemical tanks.