LOS ANGELES, CA — A fire that broke out Thursday morning at a Westlake apartment building was connected to a person’s disassembling of batteries inside one of the apartments.

Firefighters had responded at around 6 a.m. to Rampart Boulevard, between Second and Third streets, for a call regarding flowing water. Once they were in the area, crews spotted smoke coming from the third floor of a six-story apartment building at 252 S. Rampart Blvd., according to the Los Angeles Fire Department.

It’s unclear if the original call regarding water was related to the fire burning in the building.

Firefighters went up to the third-floor apartment, where a person inside had been “disassembling multiple lithium-ion batteries,” the LAFD said.

It took 45 firefighters 30 minutes to extinguish the blaze, which authorities said prompted a hazardous materials response because it was the batteries that had caught fire.

“Hazmat units are on scene mitigating any further issues with the smoldering batteries, as well as monitoring air quality for residents’ ongoing safety,” the LAFD said.

Lithium-ion batteries are commonly used in everything from smartphones to electric vehicles. They pose a rise of overheating, catching on fire or exploding when they are damaged or improperly used, charged or stored, according to the National Fire Protection Association.