Federal authorities executed a search warrant at a Southern California aerospace facility after a chemical tank overheated last month, triggering the evacuation of about 50,000 residents.

The FBI searched GKN Aerospace in Garden Grove, where agents were authorized to seize records and samples related to methyl methacrylate storage and handling.

The warrant also covers documents on cooling systems and other equipment used to regulate the hazardous chemical.

Officials are investigating how the 34,000-gallon tank overheated and whether proper safety measures were in place, NPR has reported.

The incident raised fears of a potential explosion or chemical disaster, prompting a state of emergency and large-scale evacuations.