Garden Grove chemical tank threatens explosion, forces mass North OC evacuation

A 7,000-gallon methyl methacrylate tank at a Garden Grove aerospace plant is on the verge of a catastrophic explosion or toxic chemical leak, forcing tens of thousands of North Orange County residents to evacuate, fire officials warned Friday.

Damaged valves at GKN Aerospace on Western Avenue have blocked all manual options to cool or vent the tank, leaving emergency crews facing a scenario OCFA Incident Commander Craig Covey compared to a railroad tank car explosion — with no clear way out.

"That is what we were handed: a leaking tank or a tank that blows up," Orange County Fire Authority Incident Commander Craig Covey said at a Friday afternoon news conference, according to Voice of OC.

The crisis began Thursday when a tank at GKN Aerospace on Western Avenue heated up, causing internal pressure to build until the vessel visibly bulged and its relief valve activated. Three tanks at the facility were initially involved; two have since been neutralized. The one remaining critical tank cannot be manually cooled or vented because, Covey said, "the valves are broken and gummed up with the agent." Methyl methacrylate is used in aerospace manufacturing to produce hardened plastic components.

Covey drew a vivid parallel to convey the potential scale of failure. "That tank, when it heated up on the first day, actually bulged. If you 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 half a mile down the train track – that's the incident potential we're dealing with if this suffers a catastrophic failure," he said, Voice of OC reported.

As of Friday evening, the tank's temperature stood at 61 degrees — above the 50-degree target officials called the "happy place" for stability. Crews have been cooling the exterior with sprinklers, monitoring temperature with drones and constructing sand barriers around the site. Covey said engineers from across the country were being consulted and pledged around-the-clock effort. "It is not ok with me just to sit back and watch this thing blow up or fail. That is not acceptable to me. We are going to work 24 hours a day," he said.

OC Health Officer Dr. Regina Chinsio-Kwong warned of the health risks facing anyone still in the evacuation zone. Methyl methacrylate vapor — which literature describes as having a fruity, heavy odor — "can cause a lot of irritation to your eyes, your nose, to your respiratory track – your lungs," she said, adding that prolonged exposure can produce dizziness and severe respiratory damage.

The evacuation zone covers a broad swath of North Orange County, stretching from Ball Road to Trask Avenue and Dale Street to Valley View Street. Garden Grove Mayor Stephanie Klopfenstein urged immediate compliance. "To everyone still in evacuation areas – please leave immediately. This is a serious situation," she said.

Covey was explicit that the outcome was not hypothetical. "This is not precautionary – this is going to happen unless some brilliant guy behind me here figures how we can mitigate this incident," he told reporters Friday. "At some point this is going to fail and we're doing our best to figure out the when or how to prevent it."