More than 40,000 people in Southern California remained under evacuation orders on Friday after a hazardous chemical leak at an aerospace manufacturing facility in Orange County raised fears of a possible explosion.
Authorities said a storage tank containing between 6,000 and 7,000 gallons of methyl methacrylate, a highly flammable substance used in plastic production, overheated on Thursday and began venting vapors into the air at a GKN Aerospace facility in Garden Grove.
Officials expanded evacuation zones beyond the immediate area to include parts of Anaheim, Buena Park, Cypress, Stanton and Westminster after efforts to stop the leak overnight were unsuccessful.
No injuries or deaths had been reported as of Friday evening.
Orange County Fire Authority officials said one of three chemical tanks at the facility suffered a compromised cooling system, creating what they described as a worsening risk.
Division Chief Craig Covey said authorities were preparing for two possible outcomes: the tank could rupture and spill toxic chemicals into surrounding areas, or it could enter a “thermal runaway” and explode.
“This thing is going to fail, and we don’t know when,” Covey said during a Friday news conference.
Hazardous materials teams and technical experts were working to depressurize the tank and stabilize temperatures.
Officials said crews had successfully prevented further temperature increases, although an inoperable valve complicated efforts to safely drain the tank.
Containment barriers using sandbags were also established to prevent chemicals from reaching storm drains, nearby creeks or the ocean.
Evacuation centers and an information hotline were set up as residents scrambled to leave affected neighborhoods.
Garden Grove Mayor Stephanie Klopfenstein urged residents to comply with evacuation orders, saying they were necessary for public safety.
Health officials warned that vapors from heated methyl methacrylate could cause respiratory irritation, burning eyes, nausea and headaches.
Residents near the facility described scenes of confusion and uncertainty as police officers went door to door to ensure evacuations were carried out.
Local Vietnamese-language television stations translated emergency updates for members of Orange County’s large Vietnamese community after concerns emerged that some residents might not understand English-language alerts.
Authorities said evacuation orders would remain in place while crews continued efforts to stabilize the compromised tank.