GKN Aerospace’s toxic past, Garden Grove chemical plant risks explosion

The military aerospace giant at the enter of a looming toxic chemical disaster in Southern California previously paid nearly $910,000 to settle environmental violations tied to the same facility where officials fear an overheated tank could explode as early as Monday morning.

GKN Aerospace — a major supplier of jet engines, landing gear and aircraft components for commercial and military planes — reached the settlement with the South Coast Air Quality Management District in January 2025 over permit violations, missing emissions records and nitrogen oxide issues connected to its Garden Grove plant, the LA Times reported.

The revelations resurfaced as emergency crews raced against time Sunday to contain a failing storage tank holding roughly 7,000 gallons of methyl methacrylate, a highly toxic and flammable chemical used in plastics manufacturing.

Officials warned the tank could reach a critical threshold temperature of 140F around 10 a.m. Monday — a point where the chemical may begin producing heat faster than firefighters can cool it, dramatically increasing the risk of a catastrophic rupture, toxic vapor release or explosion.

The crisis began Thursday morning when the chemical tank started overheating and venting vapors at the aerospace manufacturing facility.

By Friday, Orange County fire officials said the situation had worsened after a malfunction involving the tank’s pressure-release valve prevented crews from stopping the dangerous reaction.

Evacuation orders rapidly expanded throughout six Orange County cities — Garden Grove, Anaheim, Buena Park, Cypress, Stanton and Westminster — displacing an estimated 40,000 to 50,000 residents.

As conditions inside the tank deteriorated Saturday, California Gov. Gavin Newsom declared a state of emergency to unlock additional state resources and shelter locations.

Emergency officials described the incident as an extremely dangerous “thermal runaway” event, where the chemical generates its own uncontrollable heat inside the pressurized tank.

Under the current response plan, hazmat teams are continuing to monitor temperatures while cooling the container. Officials have acknowledged there is a point where crews may be forced to pull back entirely, leaving the tank to either rupture or explode.

“This is a very dangerous situation,” Garden Grove Mayor Stephanie Klopfenstein said Saturday while urging residents still ignoring evacuation orders to leave immediately.

According to the South Coast AQMD, inspectors uncovered multiple violations during a November 2020 inspection at the GKN facility, including absent records involving volatile organic compound emissions and permitting problems.

The agency later requested additional operational records and ultimately issued a notice of violation in April 2021.

Regulators said they continued working with GKN in the years afterward to address the permitting concerns and obtain additional documentation.

GKN Aerospace did not immediately respond to questions about the prior settlement as the chemical emergency escalated over the weekend.

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