Lawrence Douglas County Fire and Medical crews responded Wednesday afternoon to a fire at T.J. Maxx on Iowa Street in south Lawrence.

Crews were dispatched about 5:30 p.m. and located a small fire. Witnesses reported hearing an explosion before seeing and smelling smoke.

Preliminary reports suggested an air conditioning unit on the roof was responsible for the fire, which was contained to a small area and was out by 5:45 p.m. The air conditioning unit is located on the roof between World Market and T.J. Maxx, toward the north end of the shopping complex.

According to World Market employees, there was heavy smoke in the parking lot about 5:15 Wednesday evening. Employees from stores in the shopping complex said they did not hear an explosion inside the stores, but they did smell and see smoke outside and were told by firefighters to evacuate. Everyone made it out without injury.

The stores were able to reopen by 7 p.m. Wednesday and damage was reported as minimal. Lawrence Douglas County Fire Medical Division Chief Dan Green said crews determined the fire was caused by the heating unit on the roof of the building.