All remaining evacuation orders were lifted in Orange County on Tuesday evening as authorities declared there was no remaining danger of an explosion, chemical leak or fire stemming from a hazardous material incident at an aerospace manufacturing plant.
Around 50,000 people in Stanton, Garden Grove and surrounding areas were asked to evacuate during the crisis, when an overheating tank filled with 7,000 gallons of a chemical called methyl methacrylate — a highly flammable liquid monomer used to manufacture plastics — was at risk of causing a massive explosion.
Around 7:30 p.m. Tuesday, the Orange County Fire Authority announced that the decision to fully repopulate the evacuation zone was made in coordination with law enforcement, the Environmental Protection Agency and the Orange County Public Health Department.
Officials had announced Monday morning that the risk of a BLEVE, or boiling liquid expanding vapor explosion, had been eliminated after crews sprayed more than 9 million gallons of water onto the tank, drastically reducing the vessel’s temperature. As a result, the evacuation zone was initially reduced Monday evening.
On Tuesday, crews remained focused on stabilizing the temperature of the tank to eliminate any remaining fire risk, according to interim Orange County Fire Authority Chief TJ McGovern.
The six-day chemical crisis began inside the GKN Aerospace facility in Garden Grove on Thursday. It was probably caused by the failure of a cooling system designed to regulate the temperature of chemical tanks, McGovern said.
The Orange County health officer and fire officials have insisted there have been no toxic chemicals released. But some environmental experts have expressed skepticism over this claim, particularly after the high temperature inside the tank led to a crack in the vessel.
Times staff writers Hannah Fry and Tony Briscoe contributed to this report.
