FBI searches California aerospace plant after chemical tank scare

Federal agents searched GKN Aerospace Transparency Systems in Garden Grove after a chemical tank overheated and sent tens of thousands of Orange County residents fleeing from a possible explosion. The warrant turned a fast-moving industrial emergency into a broader accountability fight, with investigators now examining records, samples and cooling systems tied to the tank that triggered the scare.

The emergency began May 21, 2026, when the tank at the Southern California aerospace plant started to heat up and bulge. NBC News reported that the affected tank held about 7,000 gallons of methyl methacrylate, a toxic and flammable industrial chemical used to make plastics. Firefighters later said the risk of a boiling liquid expanding vapor explosion, or BLEVE, had been averted, and officials said a potential crack may have been releasing pressure inside the tank. KTLA separately reported that firefighters described the tank as a 34,000-gallon storage tank, a discrepancy that now sits alongside the rest of the public record.

The FBI warrant sought documents, records and samples related to methyl methacrylate, including materials tied to the storage, use or disposal of the chemical. It also authorized seizure of records on cooling equipment and any system used to control the tank’s temperature, along with samples from any tank, tote, drum, vat, vessel or container suspected of containing methyl methacrylate or other hazardous substances. That scope suggests investigators are looking beyond the tank itself and into the safeguards that were supposed to keep it stable.

The evacuation spread across multiple Orange County cities and ultimately involved about 50,000 residents. NBC reported that all evacuation orders were lifted Tuesday, with the final 16,000 evacuees allowed to return home once the risk of explosion, fire and public danger was no longer present. For nearby communities, the central question is not only how close the plant came to a catastrophe, but whether emergency planning, industrial oversight and notification systems were enough for a facility handling hazardous material near a large population center.

The case is now moving through several channels at once. The Orange County District Attorney’s Office has opened its own investigation, residents have filed a class-action lawsuit, and Garden Grove city leaders have pressed GKN for answers. At a special City Council meeting on June 9, GKN senior vice president Steve Carlin apologized and said the company was still in the early stages of determining next steps. The lawsuit identifies the plant as 12122 Western Avenue, where a company that makes cockpit windows, canopies and windshields is now under scrutiny over how a single overheated tank put an entire region on edge.