Cooling system at chemical tanks likely failed, forcing mass O.C. evacuations, fire officials say 20%
By Hannah Fry53%
5/26/2026, 9:03:37 PM
Topics: The Latest
BS Summary: This article contains 26 faulty reasoning types, including Post Hoc (False Cause), Overconfidence Bias, and Negativity Bias, with Appeal to Authority as the most egregious example at 28.3% saturation with 162 hits. Analysis detected 1,464 faulty-reasoning hits from 572 analyzed words, generating a BS Score of 34.6% and a BS Rank of 20% (13,473 of 16,813 articles). This article is better (less manipulative) than 80.10% of the article peer group.
The crisis at a Garden Grove aerospace firm that required the evacuation of 50,000 people was probably caused by the failure of a cooling system designed to regulate the temperature of chemical tanks, interim Orange County Fire Authority Chief TJ McGovern told The Times on Tuesday.
This may have led to a buildup of heat in a pressurized tank filled with 7,000 gallons of a chemical called methyl methacrylate, a highly flammable liquid monomer used to manufacture plastics.
“We don’t know why, but it stopped cooling,” McGovern said.
“So that’s what started this event, to where the product heated up ... and that’s how this whole response started.
We’re just now being able to get to the tanks, so there’s definitely more to come of what caused it.”
Officials evacuated an estimated 50,000 people on Friday after determining one of the three tanks at the aerospace company was in danger of a massive blast called a boiling liquid expanding vapor explosion, which would have caused widespread damage.
Further evaluations over the Memorial Day weekend found the tank had a crack that had reduced pressure, eliminating the possibility of a catastrophic blast.
“Yesterday we really turned a corner,” McGovern said.
The confirmation that the tank was no longer pressurized enabled members of a team — made up of experts from the Fire Authority, Los Angeles and Long Beach fire departments, Los Angeles County and San Bernardino County fire departments, and the California Office of Emergency Services — to get closer to the tank to peel back the external wall and insulation, McGovern said.
This enabled them to focus their unstaffed hose lines on the internal tank to cool the chemical more effectively, dropping the temperature to around 92 degrees.
Although authorities reduced the size of the evacuation zone on Monday, officials stressed that the danger was not over in the immediate area around the Garden Grove aerospace facility.
About 16,000 people remained under mandatory evacuation orders in the blocks immediately around the property.
But McGovern said at a Tuesday afternoon community meeting that evacuation zones could soon shrink further.
Officials were assessing whether the tank’s temperature had stabilized.
If it has and there’s no fire risk, he said, “our evacuation zones are going to shrink.”
Officials have said that the crisis did not result in the release of chemicals that could be harmful.
“I want to reassure everyone who is outside of the new evacuation zone that, when you go home, you can feel safe,” said Orange County Health Officer Dr.
Regina Chinsio-Kwong.
“There was no contamination, there were no fumes, there were no vapors that came from this incident.
There was no leak.”
On Tuesday, McGovern said officials had started shutting down one of the two water supplies that were cooling the tank and assessing how it responded.
“We’re looking for any fluctuations.
What we do not want is the internal temperature to increase because we’re shutting down the water.
We would really like it to decrease. ...
We’re looking at the stability of the internal temperature,” he said.
If the temperature remained constant, officials were set to consider shutting down the secondary water supply.
After that, if the temperature didn’t fluctuate, it would “tell us that the fire problem, or the small explosion, has been mitigated,” he said.
Times staff writer Clara Harter contributed to this report.
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