LOS ANGELES (AP) — Federal authorities served a search warrant on Wednesday at a Southern California aerospace facility where a chemical tank overheated last month, forcing 50,000 residents to evacuate.

The warrant signed by a federal judge last week approved the seizure of documents and records related to the “storage, use, or disposal” of methyl methacrylate, the chemical inside the affected tank.

“Samples of the substance within any tank, tote, drum, vat, vessel, or container suspected of containing or having previously contained methyl methacrylate and/or any hazardous substance” were also sought, according to the warrant.

The FBI confirmed its agents were searching GKN Aerospace Transparency Systems in the Orange County city of Garden Grove.

GKN Aerospace makes cockpit windows, canopies and windshields. The tank that overheated contained 6,000 to 7,000 gallons (22,700 to 26,500 liters) of methyl methacrylate, which is highly flammable Exposure to the chemical can cause serious respiratory problems, neurological issues and irritation to the skin, eyes and throat, according to the Environmental Protection Agency.