A series of explosions and a two-alarm fire forced some firefighters and police officers out of their Downtown Brooklyn station Sunday.

According to officials, construction workers were laying down tar on the roof of the building on Prince and Tillary streets when a kettle of boiling tar caught fire and spilled over. Fire officials say three 100-pound propane tanks exploded and one of them shot off the roof and landed on a Brooklyn-Queens Expressway ramp.

Authorities say all 10 construction workers made it off the roof in time. Those inside the building, which houses the police department?s 84th Precinct and the fire department?s 31st Battalion, were evacuated briefly while the fire was put out. One firefighter suffered minor injuries fighting the blaze.