A Baltimore firefighter was hospitalized after falling through the floor while checking for extension during a fire in a vacant rowhome.

Firefighters were called to a reported fire involving four vacant rowhomes on the 1800 block of Aisquith Road around 10:30 p.m., according to WMAR 2 News.

Fire crews were checking for extension in adjacent rowhomes when the firefighter fell through the floor into the basement.

The firefighter called a mayday and was assisted to safety by rescue crews with non-life-threatening injuries.

Since the South Stricker Street fire where three firefighters were killed, the department’s new operating procedure is to fight vacant structures from the exterior.