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Melon

(1,781 posts)
Fri May 22, 2026, 11:29 PM May 22

MMA tank evacuation in California. Technical explanation. An answer to 10 different assumptions in different threads. [View all]


I work in chemicals and have spent time in a methyl methacrylate plant. This is MMA. It’s downstream from either acetone or more likely propianaldehyde. In the US, this is downstream from Ethylene cracked from gas.

This is the product that’s made into acrylic. All of those clear plastic screens in front of the grocery checkout are acrylic. It’s also the thick plastic used in large aquariums, bullet proof glass etc. It’s lighter than glass, safer, and at a high level doesn’t involve strip mining to produce. It’s not consumer plastic attributed to most pollution like plastic water bottles.

MMA improperly stored or having a contaminant in the tank can cause polymerization. The liquid is basically cross linking in the tank to transform into another chemical. The waste product to that reaction is heat and pressure. This is what’s happening.

The tank is too far gone and is exponentially building heat and pressure. They can cool the tank but not stop the reaction. At some point the tank can’t handle the pressure and will rupture or explode. At this point, for safety, it’s best to turn on the hoses and back all emergency crew away. There iso no stopping it. The relief valve is either broke or more likely can’t keep up with the pressure.

I will answer questions if I know the answer. I was and am not a chemist or operator.
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Im less than 10 miles from the tank BlueWaveNeverEnd May 22 #1
On a relative basis... that's quite a ways. Melon May 22 #4
Thanks. IcyPeas May 22 #2
The water be sprayed on the tank is to dissipate heat. Melon May 22 #3
Local NBC news is saying it has cooled significantly IcyPeas May 23 #7
With the volumes that the chief is giving. I don't think it will rupture. There is room in the tank as long as Melon May 23 #8
This is likely Celsius. Those number on are cold in F. A polymerization will heat a tank over 200F. Melon May 23 #9
The runoff will surely be somewhat toxic. That is not to say that it is anything like the greatest danger involved. nt eppur_se_muova May 23 #17
Found live feedon YouTube, Garden Grove CA MerryBlooms May 23 #5
the live streams i'm seeing on youtube are filmed in daylight and it's one thirty in the morning in chgo orleans May 23 #12
I just retread an article listed on the volumes. Melon May 23 #6
Thanks for this! C Moon May 23 #10
one notices both tanks are installed in cages with sprinklers systems bathing them so this msongs May 23 #11
Are we talking explode like... druidity33 May 23 #13
It's a pressure issue. Melon May 23 #14
what about a blast mat? mopinko May 23 #15
I've never heard of one being used. Melon May 23 #16
Firefighters are approaching the tanks. Perhaps to see the temperature gauge. IcyPeas May 24 #18
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