Overview
- A storage tank of methyl methacrylate at GKN Aerospace in Garden Grove began overheating after a leak was first reported on Thursday, triggering mandatory evacuations that officials place between about 40,000 and 50,000 people across six nearby cities.
- Fire and hazardous‑materials teams have spent days spraying the tank with remote water streams, flying drone thermal checks and building sand berms to contain any spill while crews attempt to keep internal temperatures from triggering a thermal‑runaway event.
- Late in the weekend crews reported a possible crack in the tank that may be releasing pressure, a finding officials are validating because it could lower the chance of a boiling‑liquid expanding vapor explosion (BLEVE) and change response options.
- The governor declared a state of emergency for Orange County to unlock Cal OES support and federal aid, the EPA deployed continuous air monitors that have not detected an active gas release in recent checks, and Cal/OSHA plus the county district attorney have opened investigations.
- About 6,000–7,000 gallons of MMA were in the affected tank, schools and community centers were closed or used as shelters, residents faced displaced routines and legal actions have already been filed while authorities weigh when it will be safe to lift evacuations.