If you can get it out of the tank, you can prevent further runaway polymerization by adding an inhibitor like hydroquinone.

I don't understand why a storage tank for this stuff doesn't have an injection port, independent from any other pipes or valves, that could be used to add an inhibitor. Maybe it does and it's broken (clogged with PMMA from the reaction) as well?

They tried to neutralize but couldn’t apparently.

“But when members of GKN Aerospace’s response team arrived to inject a neutralizing agent into the tank to reduce the liquid’s volatility, they learned that the tank’s valves were gummed up, making the interior inaccessible, said Mr. Covey.”

https://www.nytimes.com/2026/05/23/us/garden-grove-chemical-...