All evacuation orders were raised in the OC chemical crisis; the threat is over
All remaining evacuation orders were lifted in Orange County Tuesday evening as authorities announced there was no remaining risk of an explosion, chemical leak or fire from a hazardous materials incident at an aerospace manufacturing facility.
About 50,000 people in six cities in Orange County were told to evacuate during the disaster, when a superheated tank filled with 7,000 gallons of a chemical called methyl methacrylate — a highly flammable liquid monomer used to make plastics — was in danger of causing a massive explosion.
At 7:30 pm on Tuesday, the Orange County Fire Authority announced that the decision to fully refill the evacuation zone was made in cooperation with law enforcement, the Environmental Protection Agency and the Orange County Department of Public Health.
An inspection over the Memorial Day weekend found that a crack in a tank at GKN Aerospace reduced the pressure inside, greatly reducing the risk of an explosion, according to Orange County Fire Authority interim Chief TJ McGovern. Crews were then able to pull back the exterior wall and insulation and reroute their water pipes to continue cooling the chemical inside, McGovern said.
Officials announced Monday morning that the danger of a boiling vapor explosion, BLEVE, has been contained after crews sprayed more than 9 million gallons of water from the tank.
As a result, the evacuation zone was first lowered on Monday evening, allowing about 34,000 residents to return home.
On Tuesday, crews remained focused on stabilizing the tank’s temperature to eliminate any remaining fire risk and monitoring the water flow to ensure no wastewater was escaping.
The tank was sitting at 92 degrees Monday morning, according to Fire Authority spokesman Greg Barta. The workers then shut off the water stream and analyzed the response.
Craig Covey, chief of the Orange County Fire Authority, interrupted a public meeting in Garden Grove Thursday evening to tell residents that everything had been called off.
“I just got the good news that the tank [temperature] they have been stable since the three or four hours we shut off the water,” he said, “I didn’t want to delay you coming home tonight. I am sorry to do this during this meeting, but this is more important than anything else.”
Due to “mass caution,” an exclusion zone of 300 meters, which does not affect any civilians, remains in place around the tanks as hazardous materials personnel continue to monitor the situation. Road closures are also in effect on Western Avenue between Chapman and Garden Grove boulevards.
The six-day chemical crisis began inside the GKN Aerospace facility in Garden Grove and was likely caused by a failure of a cooling system designed to control the temperature of chemical tanks, McGovern said.
Many lawsuits have been filed against the aerospace company seeking compensation for residents who were exposed to the accident and were forced to evacuate.
The Fire Authority first responded to the incident on Thursday afternoon by pouring a tank into the water and ordered people to evacuate the surrounding roads which was cleared that night.
But on Friday morning, the severity of the problem became apparent as workers were unable to cut off and remove the chemical.
The tank was deemed to be in danger of causing a catastrophic explosion and evacuation orders were issued for residents in the areas of Garden Grove, Cypress, Stanton, Anaheim, Buena Park and Westminster.
Orange County health and fire officials stressed that no toxic chemicals were released during the emergency.
“There was no pollution, there was no smoke, there was no steam from this incident,” said Dr. Regina Chinsio-Kwong, the district health officer, on Monday. “There was no leak.”
Some environmentalists have expressed skepticism about the claim, saying that at least some steam may have escaped from a crack in the tank.
Times staff writers Hannah Fry and Tony Briscoe contributed to this report.
