Firefighters from three departments spent 40 minutes trying to control a house fire that broke out shortly before 4 p.m. Saturday. A firefighter also was injured while on duty. More than 40 firefighters battled the blaze that appeared to have started at the back of the 1.5-story single-family home and involved the rear deck area at 1887 Cedar Dr. According to a report from the Anne Arundel County Fire Department, a recreational vehicle also was involved in the fire. The Red Cross is helping four adults who have been displaced. A firefighter from Fort Meade Fire and Emergency Services suffered a minor ankle injury while moving a hose line and was transported to UM Baltimore Washington Medical Center for treatment. Paramedics evaluated an occupant with a hand injury on the scene but the individual did not require transport to the hospital. The cause of the fire is being investigated by members of the Anne Arundel County Fire Department Fire and Explosives Investigation Unit.