Firefighters in Garden Grove have been dousing a bulging tank at a GKN Aerospace plant with water to keep the chemical inside from reaching explosive pressure. The tank holds roughly 7,000 gallons of methyl methacrylate, a low‑boiling plastic precursor that can vaporize quickly when overheated. Officials fear a combustion event could launch a fireball comparable to a house‑sized blast.

Around 40,000 residents have been ordered to evacuate to shelters in Garden Grove, Cypress and Anaheim, reflecting uncertainty about where a possible fireball might land. Fire crews built sand barriers to keep the chemical from entering storm drains, while attempts to inject a neutralizing agent failed because gummed‑up valves blocked access. Engineers warn pressure may already exceed safe release limits.

The incident underscores operational risks for aerospace suppliers that store large volumes of volatile chemicals near dense populations. With GKN employing roughly 540 workers at the Garden Grove site, any escalation could disrupt supply chains for major aircraft manufacturers such as Airbus and Boeing. County authorities continue to monitor temperature and pressure readings, keeping the public on high alert until the tank is stabilized.