Although the Orange County Fire Authority has ruled out the threat of a highly destructive pressurized explosion at an aerospace plant in Garden Grove, the area remains at risk of a smaller but potentially dangerous blast or a spill.
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Since Thursday, May 21, when workers at GKN Aerospace reported problems in a tank containing methyl methacrylate, also known as MMA — a flammable, volatile chemical used in plastics and manufacturing — OCFA officials have been working to mitigate what they deemed a “worst-case” scenario, a “boiling liquid expanding vapor explosion,” or “BLEVE.”
On Monday, May 25, fire officials said a BLEVE blast is “off the table,” because a crack in the container has helped to lower the chemical’s temperature. But they also said that they still have questions about what the state of the MMA and what danger it might still pose.
Also see: What a crack in the tank means, and why liquid nitrogen is a bad idea
“The MMA is still in the container. We don’t know how much is solidified and (how much is) still in its liquid form… When it’s in liquid form, it is still very hazardous, it’s still very volatile and dangerous to human health,” said OCFA Fire Captain Brian Yau by phone Monday afternoon.
Yau said there are currently two threats: the flammability of the MMA, which could lead to a small-scale explosion, and the risk of vapor leaking from the tank and exposing the population to a chemical that that can cause respiratory problems, dizziness and nausea.
In liquid form, MMA is still flammable and can generate heat on its own, Yau said. An explosion remains possible, he added, if the chemical is “exposed to a heat source, or it generates heat on its own.”
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“We’re still trying to determine the extent of that risk, which is why we are working on the evacuation zone and determining what’s going to be the next best course of action,” Yau said.
Also see: How worried should you be about a Garden Grove chemical spill or explosion’s impact on your health?
The update follows a nighttime operation in which OCFA crews discovered the crack that relieved enough pressure to prevent an explosion that could have damaged buildings and released a toxic vapor cloud.
Evacuation orders for roughly 50,000 residents in Garden Grove and nearby communities have remained in effect for four days through the holiday weekend.
Also see: How OC evacuees can get assistance during the chemical threat
In a video statement, Garden Grove Mayor Stephanie Klopfenstein said the city will not hold its regularly scheduled city council session and will instead hold a special meeting at 5:30 p.m. at the Community Meeting Center, 11300 Stanford Ave, Garden Grove. The meeting will focus on incident details and the city’s response.
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