All evacuation orders tied to a hazardous materials incident at a Southern California aerospace facility were lifted Tuesday night, officials said, clearing about 50,000 people to return home after a damaged chemical tank threatened to explode.
Orange County Fire Authority Division Chief Craig Covey told residents at a meeting, “All residents will go home,” after authorities lifted the final evacuation order for neighborhoods near the GKN Aerospace Transparency Systems plant in Garden Grove. Authorities said the tank contained the highly flammable chemical methyl methacrylate, or MMA.
Officials said a crack that formed in the tank over Memorial Day weekend relieved pressure and helped avert a catastrophic explosion, allowing most evacuees to return. Still, roughly 16,000 residents remained under evacuation orders heading into Tuesday, authorities said.
Crews sprayed water on the tank until its interior temperature stabilized at 92 degrees, down from about 100 degrees over the weekend, and a sprinkler system also doused the tank while company specialists and firefighters removed insulation to cool it, authorities said. Evacuation orders were lifted after the tank’s temperature remained stable for four hours without assistance from the sprinkler system.
Health officials said monitoring had not detected hazardous levels of contamination or fumes but that air quality, sewer systems and storm drains would be monitored for several months. The Environmental Protection Agency says exposure to MMA can cause serious respiratory problems, neurological issues and irritation to the skin, eyes and throat.
Garden Grove Mayor Stephanie Klopfenstein said she plans to hold the company accountable. GKN said in a statement it was working closely with authorities and apologized for the disruption, adding that “our priority remains the safety of our neighbors and our community.” Officials said crews first responded Thursday to vapor releasing from a storage tank at the facility, which makes engine structures and other products for commercial and military aircraft. Gov. Gavin Newsom declared a state of emergency Saturday as crews shifted tactics, and Orange County Fire Chief T.J. McGovern told the Los Angeles Times that investigators are looking into a possible cooling-system failure that may have allowed heat to build in a pressurized tank containing 7,000 gallons of MMA. “We don’t know why, but it stopped cooling,” McGovern said to the newspaper.
Jon Ross Myers is the executive editor and publisher of the Mississippi News Network, Mississippi's largest digital only media company. He can be reached at editor@tippahnews.com
