A rapidly escalating chemical emergency at an aerospace facility in Garden Grove, Orange County, has raised fears of a potential explosion or large-scale toxic release.

The crisis centers on a pressurized tank containing approximately 7,000 gallons of methyl methacrylate (MMA), a highly reactive chemical used in industrial processes.

Officials report that the internal temperature of the tank has risen from 77 degrees to 90 degrees in a short period, moving closer to the chemical’s boiling point and increasing the risk of a dangerous reaction known as thermal runaway.

Fire authorities and chemists believe the heat inside the tank is being generated by MMA monomers reacting and forming polymers, a process that releases energy and can accelerate uncontrollably.

The main complication is that a valve needed to inject a neutralizing agent is clogged, leaving officials unable to directly stop the reaction or drain the tank.As a result, responders are relying on continuous water spraying to cool the exterior of the tank and slow the internal chemical reaction.While this method is not reducing the internal temperature directly, experts say it is helping slow the rate of heating and buying time.Authorities have outlined two worst-case outcomes: a catastrophic explosion or a hazardous chemical leak.

However, a potential third option has emerged—allowing the reaction to proceed slowly under controlled cooling so the chemical solidifies safely inside the tank.

Evacuation orders affecting up to 40,000 residents remain in place across several nearby cities, as officials continue monitoring the situation and working to prevent a disaster.