A three-alarm fire ripped through the Navy Yard Friday for the second time this week, lightly injuring six firefighters.

Fire officials say the blaze broke out on the third floor of a vacant building at 15 Washington Ave. where a contractor was doing welding work on the ceiling. The flames quickly spread to the fourth floor, sending black, thick clouds of smoke into the air.

There were 15 workers inside the building at the time of the fire, but none of them were hurt. The fire chief who was at the scene says the contractors were not to blame in the fire.

The vacant building was being renovated for Steiner Studios that will be taking over the space.

On Tuesday, another fire broke out inside a Navy Yard building on Flushing Avenue and Cumberland Walk. The fire officials, however, are calling it a coincidence.

?We will be talking to the Navy Yard folks next week about maybe some safety issues,? the fire chief says.

According to firefighters, Friday?s blaze caused some asbestos abetment inside the building, but they say it was contained, and the site was subsequently inspected by the Environmental Protection Agency.