All evacuation orders lifted in Garden Grove, CA for the GKN Aerospace toxic chemical incident

This evening the Orange County Fire Authority announced that all evacuation orders related to the Garden Grove hazardous materials incident have been lifted.

Unified Command (Fire, Law, EPA, and County Health) have confirmed there is:

No chemical leak

No threat of explosion

No threat of fire

No risk to the public

The OCFA released this revised map:

Map Details:

Green shaded area on the map = Repopulation area

Red line = Road closure (Western between Chapman & Garden Grove Blvd.)

Red circle = An exclusion zone to allow hazardous materials teams to continue monitoring the tanks out of an abundance of caution (no residents affected).

The OCFA also announced earlier today that the tank temperature had stabilized at 92° F and that they had secured all of the other nearby tanks.

No further details are available at this time.

Have any of you been physically affected by methyl methacrylate monomer before?

 Just a little sidebar about the hazardous chemical tank incident in Garden Grove, CA.

The chemical of concern is methyl methacrylate monomer. When it polymerizes and turns into a solid, it gives off a lot of heat because the polymerization is an endothermic reaction.

Methyl Methacrylate molecule, Photo Credit: Jynto

Anyway, a long time ago (1973-74), I used to work for a carbide tool manufacturer in Latrobe, PA, called Kennametal. They were famous for making tire studs for winter tires, welding rods, and carbide tool bits.

We were experimenting with different mixing agents for the carbide powders used in the processes, including methyl methacrylate monomer.

One day I went home after work and suddenly started getting horrible hives. They were huge and covered my arms, legs, and other parts of my body. We weren't sure what caused it, but, the only thing different from what I usually did there was that I was in the lab when they were experimenting with methyl methacrylate. I remember the strong odor of it. My doctor suspected that was the cause. It took a week or two for all the hives to disappear.

A few months later I resigned and went to grad school to study environmental science. One day I was walking up the stairwell in one of the chemical lab buildings. The floor tiles were being replaced and I smelled a familiar odor. When I got to my apartment, I broke out in hives again, just like before. I later found out that methyl methacrylate was one of the chemicals being used to secure the floor tiles to the stairway!

In all of the reporting being done about this incident in Garden Grove, I don't recall anyone discussing this effect of the chemical on some people.

Have any of you had a similar experience? Let us know in the comments below.

Was the company responsible for the hazardous chemical incident in Garden Grove in compliance with hazardous chemical storage requirements?

By now, most of you have heard of the ongoing emergency in Garden Grove, CA, revolving around a disastrous failure of a storage tank containing methyl methacrylate. Fears of a massive spill and/or explosion have resulted in the evacuation of thousands of residents from their homes since last Friday.

Photo Credit. GKN Aerospace logo (fair use)

Emergency response authorities such as the Orange County Fire Authority (OCFA) have done a great job in keeping the public informed of the current status of the emergency response. We have discussed the incident in previous articles in this blog.

However, one thing we have not personally seen, but, perhaps our readers have, is whether anyone has addressed the following:

Did GKN Aerospace Transparency Systems, the owner of the tank in question, follow/comply with required federal/state/and/or local requirements and procedures for the storage of hazardous chemicals, including the existence of an emergency response plan if required?

In all of the news reporting that we have seen (including our own) nobody has addressed this fundamental issue.

• What federal, state, and/or local regulations for the storage of methyl methacrylate, if any, applied to this facility?
• Was an emergency response plan required and in place, and if so, did GKN follow it? 
• If GKN did follow it, what went wrong in this particular situation that required outside agencies to be called in to take over the response?

It should be noted that in January of last year, GKN settled alleged violations of the South Coast Air Quality Management District (SCAQMD) rules and regulations to the tune of over $900,000. The Orange County Register recently reported on this in more detail. 

To be perfectly clear, we are making no accusations of wrong-doing on the part of anyone. We just would like someone to address whether the company was in compliance with existing regulations and emergency plans or not. 

And, if they were in compliance, was this particular situation, involving a tank of methyl methacrylate monomer that apparently started to polymerize and uncontrollably heat up while a control valve failed, addressed in existing plans or was it simply an unforeseen circumstance?

Please let us know in the comments below if you have any information regarding the above questions, or, if you have any other comments.

Risk of Explosion from Garden Grove Toxic Chemical Tank Eliminated per OCFA

In a video update made this morning by the Orange County Fire Authority (OCFA), the risk of the methyl methacrylate tank experiencing an explosion, otherwise known as a BLEVE (Boiling Liquid Expanding Vapor Explosion) has been eliminated.

Photo Credit: Screenshot of OCFA Incident Update, 5/25/26

According to the OCFA, temperatures in the tank have been measured as decreasing from a high upwards of !00° F to current levels at 93° F. Additionally, pressure in the tank has been reduced due to a crack found in the tank wall.

Nevertheless, the mandatory evacuation order remains in place until the threat of a potential major spill is eliminated.

We have previously provided details on this extremely hazardous toxic chemical storage tank emergency in Garden Grove, CA, in the following two articles:

• California Governor Newsom Declares State of Emergency for Orange County for Garden Grove Chemical Tank Incident 
• Mandatory Evacuation Orders issued in Garden Grove, CA, due to hazardous chemical storage tank emergency.