The tank at GKN Aerospace is estimated to contain 7,000 gallons of methyl methacrylate, a volatile chemical used to produce plastics.

About 40,000 people are under evacuation orders and schools have shut down in Southern California due to a hazardous chemical leak.

Authorities in Orange County say they’re unable to control the valves on a tank that contains methyl methacrylate, a chemical used in the manufacture of plexiglass.