Orange County officials are urgently working to cool a toxic chemical tank containing methyl methacrylate (MMA) after temperatures inside the tank rose to 90 degrees, despite earlier reports suggesting stability. The tank, which holds 7,000 gallons of MMA, is at risk of rupturing or exploding, potentially releasing a toxic cloud over Garden Grove. Officials have evacuated 40,000 residents as a precaution.
First responders initially measured the tank’s exterior temperature via drone, leading to incorrect assumptions about the internal temperature. Fire officials later discovered the liquid inside was rising by one degree per hour, prompting concerns of a thermal runaway reaction—a dangerous, self-sustaining chemical process. Division Chief Craig Covey of the Orange County Fire Authority emphasized that crews are working 24 hours a day to mitigate the crisis, though the situation remains volatile.
MMA is highly toxic in its liquid form, capable of causing respiratory irritation, skin damage, and eye injuries upon exposure. While the polymerized form is safe for use in plastics, the monomer (liquid MMA) poses significant risks. Experts warn that if the tank exceeds a critical temperature threshold, it could trigger a BLEVE (Boiling Liquid Expanding Vapor Explosion), a catastrophic event that would release toxic fumes and debris.
Officials have not yet determined a definitive solution, though cooling the tank to 50 degrees is a priority. If successful, this could allow for safer containment or controlled release. Meanwhile, residents remain on high alert as authorities monitor the situation.