Boston firefighters responded to a six-alarm fire in Charlestown Thursday afternoon.

The blaze began around 1:45 p.m. Thursday at 284-286 Bunker Hill St., authorities said. 

The home was a four-story brick and wood duplex building. 

No residents were injured, but one firefighter was transported to Massachusetts General Hospital to get checked out.

All of the residents in the 13 units in the two buildings were displaced, firefighters later said. 

At one point, firefighters sounded a mayday distress call, but it was canceled when two firefighters missing in the flames were located, the Boston Globe reported