Orange County officials say a chemical tank in Garden Grove is in “unprecedented” danger of failing or exploding, prompting an evacuation request for about 40,000 residents across several cities. The chemical, methyl methacrylate, can release toxic vapors and
For thousands of people in Orange County, Friday began with a countdown they couldn’t see.
At a facility in Garden Grove on the 12. 000 block of Western Avenue. three large tanks holding a highly toxic chemical called methyl methacrylate—used to make plastic—were in crisis. Fire officials warned the situation was “unprecedented,” and they said they could not recall anything similar happening before. The most compromised tank, they said, still held about 7,000 gallons of the chemical and had been overheating since Thursday.
By mid-afternoon Friday, officials said they were asking about 40,000 residents to evacuate portions of Garden Grove, Anaheim, Buena Park, Cypress, Stanton and Westminster. Disneyland was outside the evacuation zone.
“This is highly volatile, it’s highly toxic, it’s highly flammable,” Craig Covey, a division chief with the Orange County Fire Authority and the incident commander, said at a briefing.
Officials laid out the stark choice they were preparing for: either the tank fails and cracks and the chemical leaks onto the ground, or it suffers an uncontrolled explosion.
“One, it fails and cracks, and all the product leaks out onto the ground,” Covey said. He described efforts to keep the liquid from reaching storm drains and river channels and into oceans. In that best-case pathway. teams in hazardous materials suits could move in to “neutralize and mitigate the vapors that will be coming off of that.”.
The worst case, Covey said, is an explosion that could send fire and debris far beyond the site.
“If you’ve ever seen videos of tank cars on a railroad track blowing up, and that fireball it puts out, and it blows half the tank car a half a mile down the train track, that’s the incident potential we are dealing with if this suffers a catastrophic failure,” he said.
At the same briefing, Covey described the urgency in plain terms. “Those were the options: ‘a leaking tank or a tank that blows up,’” he said. “This is going to happen unless some guy behind me here figures out how we can mitigate this incident. This thing is going to fail. We don’t know when.”
The tanks involved are at GKN Aerospace, which builds engine structures, landing gear and other products for commercial and military aircraft.
The chemical risk is why the evacuation order is so wide. MMA is very toxic. Dr. Regina Chinsio-Kwong, Orange County’s health officer, said short-term exposure from inhaling MMA vapors can cause significant irritation in the lungs and nasal passages, along with nausea and dizziness.
At very high exposure levels, she said, MMA can lead to severe respiratory distress and hospitalization.
Officials said the evacuation is large in part because of the possibility of a plume of toxic vapors. They said the chemical is heavier than air. so after an explosion it would settle into the lower areas around the facility. They were also planning for the danger of the chemical lingering near the ground as vapor. noting that methyl methacrylate can “easily evaporate and linger near the ground.”.
U.S. Environmental Protection Agency guidance cited in officials’ discussion said the fumes can aggravate people’s lungs, causing coughing, wheezing and chest tightness. The chemical can also cause nausea, dizziness and skin irritation.
While the EPA has classified MMA as “not likely” carcinogenic to humans, Chinsio-Kwong said long-term exposure has been linked to serious organ damage.
Officials said their ability to stabilize the tank is limited by what they found inside it. Of the three tanks, crews were able to add a chemical to one tank to neutralize its volatility, Covey said. They haven’t been able to do that with a second tank, though it is not in crisis.
But the tank in the greatest crisis. Covey said. has valves that are broken and “gummed up. ” preventing stabilizing chemical from being added to the explosive chemical. Orange County Fire Authority division chief Nick Freeman said the broken valves also mean crews can’t drain the tank of the explosive chemical.
“We are unable to get anything out, and we were unable to get anything in to stabilize these things,” Freeman said.
With options narrowing, officials said they assembled a team to look for alternatives. Covey said they are “calling people all over the state and the country to get together with ideas how we can safely go in there and depressurize a pressurized tank and mitigate the exposure that it has.”
The emergency began developing Thursday when one of the three tanks started experiencing an increase in temperature. Interim Orange County Fire Authority Chief TJ McGovern said a relief valve was activated and an overhead sprinkler system was activated to cool down the chemical.
Covey said the tank in greatest crisis was already bulging on Thursday and that it reached a point where it “does what we call a BLEVE,” which stands for “boiling liquid expanding vapor explosion.”
Officials initially had success cooling the tanks with sprinklers, Covey said, but conditions worsened Friday when they learned they could not offload a neutralizing agent into the failing tank because the valves had broken and were gummed up.
As of mid-afternoon Friday, officials said there was no active toxic release from the tank. Covey said they had cooled it down enough that the “purge valve that is on top of it is no longer purging any kind of product,” adding, “There’s nothing in the air right now.”
Still, one of the tanks released vapor on Thursday after its temperature increased. In response, officials said they activated the relief valve and cooled the tank with the overhead sprinkler system.
Officials are also trying to determine how close the tank is to catastrophic failure. Covey said drones are monitoring the temperature of the tank. He said there is a set temperature threshold—when the tank reaches it. officials will pull people out of the area to ensure safety and then let the tank “do what it’s going to do.”.
Evacuation compliance has become another pressure point. Garden Grove police chief Amir El-Farra said most people are evacuating, but about 15% are refusing to evacuate.
When asked whether the evacuation could last for days, El-Farra said he did not have an answer.
The evacuation zone is roughly between one to three miles from the failing chemical tank, which is located northeast of the corner of Western Avenue and Lampson Avenue.
Residential homes are less than 400 feet east of the tank in the city of Stanton.
Even outside the evacuation zone, officials moved to protect people. The Orange County Superior Court recommended that nonessential personnel leave the courthouse in Westminster, which is outside the evacuation zone.
For families near Western and Lampson, the frightening part is not only the potential explosion—it’s the uncertainty of when it could happen. Officials said they can’t predict the timing, only that the tank is moving toward failure.
Orange County Garden Grove evacuation methyl methacrylate chemical tank MMA BLEVE Orange County Fire Authority