Orange County residents file class action over Garden Grove chemical tank crisis

Orange County residents — represented by Zimmerman Reed LLP — filed a class action complaint in California Superior Court, County of Orange, against GKN Aerospace Transparency Systems Inc., GKN Aerospace Services Ltd., and Melrose Industries PLC over the failure of a chemical storage tank at the company's Garden Grove facility that forced approximately 50,000 residents to evacuate beginning May 21.

The complaint, brought on behalf of four named plaintiffs and a proposed class of evacuated residents, alleges that GKN's negligent storage, monitoring, and maintenance of a tank containing approximately 7,000 gallons of methyl methacrylate (MMA) — a flammable chemical the EPA classifies as a hazardous substance — created the conditions for a multi-day public safety crisis. California declared a state of emergency on May 23, President Trump approved a federal Presidential Emergency Declaration on May 25, and the Orange County District Attorney has opened an investigation.

"Fifty thousand people were told to leave their homes," said Caleb Marker, partner at Zimmerman Reed and counsel of record on the complaint. "This case is about what made that crisis preventable — and about accountability for families left to carry the cost of someone else's failure to safely maintain hazardous chemicals next door to their neighborhoods."

The allegations

The complaint alleges that on May 21, 2026, a tank at GKN's facility at 12122 Western Ave. in Garden Grove containing approximately 7,000 gallons of MMA began to overheat. Emergency responders determined that critical safety mechanisms — including a pressure-release valve — were malfunctioning, leaving authorities unable to relieve pressure, offload the chemical, or stabilize the tank through ordinary mitigation. Orange County Fire Authority officials issued warnings regarding the tank rupturing or entering thermal runaway, resulting in a catastrophic explosion. Operational maps cited in the complaint indicated that, in the event of catastrophic failure, an elementary school and roughly 200 nearby homes lay within projected zones of severe or moderate damage.

By May 23, mandatory evacuation orders affected an estimated 50,000 residents across a nine-square-mile area encompassing parts of Garden Grove, Stanton, Anaheim, Cypress, Buena Park, and Westminster.

The crisis is ongoing. As of Tuesday morning, approximately 16,000 residents remained under evacuation orders while Orange County Fire Authority crews continued work to stabilize the tank. Officials have indicated that while the threat of a catastrophic explosion has been eliminated, the risk of a smaller-scale failure or leak remains, which is the reason evacuation orders continue for the affected zone.

The four named plaintiffs each live within approximately 1.5 miles of the facility. The complaint alleges they were forced from their homes under official warnings that the tank could fail or explode, in some cases without sufficient time to gather essential belongings. They were displaced for days, incurring costs for emergency lodging, food and replacement essentials amid reports of high demand and inflated prices, while waiting under continuing uncertainty about when it would be safe to return.

"The full impact of this incident is still unfolding," Marker said. "But for many residents, something has already been lost: the sense that home is safe. That does not simply return when evacuation orders lift."

The proposed class includes all persons subject to the OCFA mandatory evacuation order as of May 22, 2026, with a subclass of property owners.

According to the complaint, GKN's Garden Grove facility has a history of documented regulatory violations at the same site. In January 2025, GKN settled with the South Coast Air Quality Management District for $909,935.95 over violations of permit, record-keeping, and emissions requirements. Additional regulator notices were issued as recently as March 2025. Earlier penalties from Cal/OSHA in 2018 cited inspection and maintenance failures at the facility.

The complaint asserts seven causes of action: negligence, premises liability, private nuisance, public nuisance, trespass, strict liability for ultrahazardous activity, and violations of California's Unfair Competition Law. It seeks class certification, damages, injunctive relief requiring safety reforms, and punitive damages.

The case is Guadarrama et al. v. GKN Aerospace Transparency Systems Inc. et al., filed in the Superior Court of California, County of Orange.

California state court

The complaint was filed in California state court, where plaintiffs seek relief under California law for harms that occurred in California communities.

"State court is where this case belongs," Marker said. "The harm happened in California, and the people who lived through it deserve to have it answered under California law."