Around 40,000 residents in Southern California remained under evacuation orders on Friday after a hazardous chemical leak at an aerospace plastics facility in Garden Grove raised fears of a possible explosion. Authorities said a storage tank containing between 22,700 and 26,500 litres of methyl methacrylate — a chemical used in manufacturing plastic aircraft components—overheated on Thursday and began releasing vapors into the air at a facility operated by GKN Aerospace.

Emergency officials expanded evacuation zones overnight to include parts of Cypress, Stanton, Anaheim, Buena Park and Westminster after crews failed to contain the leak. Schools in affected areas were shut as a precaution. Orange County fire officials warned the tank could rupture or explode due to rising internal pressure. Hazmat teams continued efforts to stabilise the situation while residents were urged to avoid the area and follow emergency instructions.