Crews have confirmed that a crack inside a malfunctioning chemical tank at a Garden Grove aerospace plant is indeed reducing pressure inside the container, leading fire officials to say they have turned a corner in heading off the most catastrophic threat — a massive explosion.
Data collected from an “all-night mission” by fire crews determined that the threat of a a highly destructive blast known as a “boiling liquid expanding vapor explosion,” or “BLEVE,” has been eliminated, interim Orange County Fire Authority Chief TJ McGovern announced in a Monday morning, May 25, video update.
“The crack is there,” Division Chief Craig Covey added. “We had identified it is there, and the tank has released it pressure.”
After days of often dire warnings by fire officials and experts, the Monday morning announcement was the most optimistic update yet by those working to head off a potential disaster. A boiling liquid expanding vapor explosion — which would have likely caused massive damage and released a toxic chemical plume into the air — occurs when a sealed, pressurized container holding a liquid chemical ruptures.
“The threat of a BLEVE is off the table,” McGovern said. “That threat has been eliminated.”
While the worst potential outcome to the crisis appears to be off the table, the evacuation of tens of thousands of residents in Garden Grove and nearby communities remains. Those evacuations have lasted for four days, through the holiday weekend.
“We want to be clear that the evacuation zones are still in play,” McGovern said.
The temperature inside the tank has also gone down, from at least 100 degrees to 93 degrees, the chief said. That is a key metric: At a high enough temperature, the chemical process was at risk of accelerating out of control — which could lead to a massive explosion.
Addressing concerns from some in the community about the lack of regular updates on that internal tank temperature, Covey said that authorities had been allowing the tank to “settle” during the warmer hours and then sending crews in to check on it during the cooler overnight hours.
“We were not doing tank temperature checks during the day when the sun was on it in the most extreme conditions for that tank to go in the wrong direction,” the division chief said. “We were only doing tank temperature checks at night.”
The discovery more than a day earlier of the crack in the compromised tank at GKN Aerospace on Western Avenue buoyed officials, who hoped it would relieve enough pressure to prevent a massive explosion that could damage buildings and release a toxic vapor cloud or a spill that could unleash 7,000 gallons of volatile chemicals.
The compromised tank is filled with 7,000 gallons of methyl methacrylate, a highly flammable chemical and in a worst-case scenario, a blast could damage hundreds of homes and buildings and create a toxic plume.
Air quality experts, who have been tracking the atmosphere near the tank, have not reported detecting any contaminants so far. The current evacuation zone — which was crafted in consultation with the EPA and OC Health Care Agency — is meant to be large enough to prevent residents from being at risk in the most catastrophic potential outcomes.
The roughly 50,000 resident of six cities impacted by the evacuation — Garden Grove, Stanton, Westminster, Cypress, Buena Park and Anaheim — were urged to remain out of the area on Monday.
Emergency crews — aided by experts from around the state and country — have been working since Thursday to come up with a way to prevent a massive explosion or chemical spill.
They have been aided by nearly 800 state and local emergency workers who are helping with evacuations, traffic, sheltering the displaced residents, monitoring the environment and protecting the empty homes and businesses.
A state of emergency in Orange County was declared by Gov. Gavin Newsom on Saturday afternoon, opening the way for those extra resources.
While bringing the crisis to a close has been the main focus, the owners of GKN Aerospace have already come under heavy criticism for the apparent failure of any emergency systems involving the chemical tank. Orange County District Attorney Todd Spitzer has already announced that his office is investigating. And at least half a dozen law firms pledged to file lawsuits seeking class-action status on behalf of residents and businesses impacted by the evacuations.