Spill or Explosion? There Are No Good Options Left

Added: 2026-05-25

[00:00:00]Around 40,000 people have been evacuated due to a critical incident involving a 34,000galon chemical tank. Now, the incident itself has been going on for roughly 2 days. And the situation, it doesn't appear to be getting any better.

[00:00:13]This is Stashed. I'm Pat, mechanical engineer and firefighter.

[00:00:17]At around 3:30 in the afternoon on Thursday, May 21st, 2026, Orange County Fire responded to GKN Aerospace in Garden Grove, California. A 34,000galon storage tank containing an industrial chemical called methylmethylryate, MMA, had overheated and was venting vapors into the air. Thankfully, the tank itself, it wasn't full, and it only contained about 6,000 gallons of product. GKN Aerospace manufactures acrylic plastic components, and it's for things like cockpit canopies or transparent aircraft panels. MMA is the raw chemical feed stock they use to produce those parts. When the fire department first arrived, the tank's own safety systems had already activated. A pressure relief valve had opened up to vent pressure on the top, and an on-site sprinkler system kicked in to start cooling the tank itself. For a while, it looked like it was working. The temperature stabilized, but then around 4:00 a.m. on Friday morning, things started to go bad. The temperature was climbing again, and unfortunately, there was a faulty valve on the tank. So, there's no easy way to get that product out of the tank itself. At this time, crews are left spraying water on the outside of a tank they can't drain, hoping to keep that temperature down long enough to find another solution.

[00:01:29]Currently, around 40,000 residents in the area are being asked to evacuate.

[00:01:33]And it sounds like about 15% of them decided to stick around. I'm just about to 75,000 subscribers. My goal is 100K this year. So, let's talk about what MMA actually is and what's going on here. I spent a long time in the auto industry working on research and development projects. Not too long ago, one of my projects involved polyurethane and polyurethane components. Most people know polyurethane as a woodworking finish, but it's widely used in many forms from spongy foams to that you might find in a mattress all the way to a hard plastic part. But it all starts as a two-part mixture, isocyanate and polyol. When you mix those two together, it's an exothermic chemical reaction, meaning it gives off a lot of heat. If you mix it improperly, it can actually heat up significantly and might start a fire. MMA is a similar idea. It's a reactive monomer, but there's a big difference there. Monomer, it can react with itself. All it needs is enough heat or the loss of the stabilizer and it starts polymerizing on its own. If that happens, it ends up going into a self-heating thermal runaway and it's pretty much impossible to stop. All the fire department can really do is cool that tank and avoid a catastrophic failure. at least hopefully avoid that catastrophic failure. MMA is also very flammable in both the liquid and vapor form. It's toxic to the respiratory system, and in this case, the tank sits right next to two other large storage tanks. Currently, they're expecting one of two things to happen, and neither of those options are good. Option one, the tank fails structurally, and it dumps right around 6,000 gallons of this MMA into the parking lot. They do have containment barriers already in place and that's going to keep it out of the waterways and the storm drain system.

[00:03:13]And while that sounds like a bad outcome, it's actually the better of the two scenarios because option two, it's an explosion that could easily take out the neighboring tanks causing a much larger problem. Now, I'm hoping for a third option. Fire crews will continue to cool the tank and eventually the chemical reaction will run its course without incident. Although, I'm seeing reports that temperatures are continuing to rise. So option three, it's not looking too feasible, but I'm an optimistic guy.

[00:03:39]>> I know there's a lot of anxiety over this. I just need you to understand we are not giving up. We are not accepting the fact that we just to let to let this thing fail. We're going to try to find a solution. We're working 24 hours today to do it. We had members down range last night at 4 in the morning. We're going to do everything we can to mitigate this, protect your residences, protect our environment, and get you back home.

[00:04:04]As of now, there's no active plume in the air. Air monitoring is ongoing. No injuries have been reported and the crews are still on scene. It would be interesting to know what actually caused this. It easily could have been just a mistake in the manufacturing process.

[00:04:18]But ultimately, the faulty valve may have made that situation worse. And it sounds like the valve wasn't necessarily faulty. It was more that the material itself was reacting in that valve and gummed up the works. I would imagine if crews had a way to empty that tank Thursday night, we wouldn't be talking about this right now. This incident is going to raise some questions about industrial chemical storage near residential areas. It may eventually lead to some conversations around safety systems, too, looking at redundancy.

[00:04:45]Because if your only solution is a single valve, you're kind of screwed if things don't work right.