40,000 Southern Californians ordered to evacuate amid threat of chemical explosion

U.S. news40,000 Southern Californians ordered to evacuate amid threat of chemical explosion 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. Listen to this article with a free account00:0000:00Water is sprayed on a tank that overheated at an aerospace plant in Garden Grove, Calif., on Friday.Jeff Gritchen / The Orange County Register via APShareAdd NBC News to GoogleMay 22, 2026, 6:35 PM EDTBy Dennis RomeroAn estimated 40,000 people in Orange County, California, have been ordered to evacuate over fears that a tank containing a toxic chemical may explode, officials said Friday.Subscribe to read this story ad-free Get unlimited access to ad-free articles and exclusive content.Authorities in Orange County said they’re unable to control the valves on a tank at an aerospace manufacturing facility in Garden Grove. “It fails or it blows up,” said Craig Coby, Orange County Fire Authority incident commander at the scene.Initial evacuation orders were issued Thursday after a “vapor release” at the manufacturing site in Garden Grove. The situation seemed to be stable, but on Friday, the valve on a tank became inoperable, the Orange County Fire Authority said.The tank contains methyl methacrylate, a toxic chemical used to manufacture resins and plastics. In a video announcement, Coby urged caution for people in the area of the leak, which includes parts of the cities of Garden Grove, Cypress, Stanton, Anaheim, Buena Park, and Westminster.Garden Grove is about 35 miles southeast of downtown Los Angeles.“It is a highly toxic substance,” OCFA Division Chief Nick Freeman said at an afternoon news briefing. “It’s extremely flammable, and in its current state, very reactive, and can cause that explosion.”The tank was not emitting the chemical on Friday, authorities said, and no injuries have been reported.Dr. Regina Chinsio-Kwong said the emergency is unprecedented and...