ST. PETERSBURG, Fla. (WFLA) — Crews battled a 2-alarm fire at a large warehouse in St. Petersburg on Thursday evening.

St. Petersburg Fire Rescue said it responded to the warehouse at 2350 31st Street South around 7:30 p.m. When they arrived, heavy smoke filled the building.

Due to the size of the building and the amount of smoke, crews said they called in more units with a second alarm.

Firefighters said the building has been cleared of the smoke. The fire was held back with fire sprinklers. Crews said they are using water to cool the area.

St. Petersburg Fire Rescue said it is not sure what caused the fire yet.

Investigators said they are waiting for the building to be safe enough to enter.