1358 hours. Commack Fire Department is activated to a report of a house fire at 68 Rensselaer Drive. Arriving units encountered a heavy fire condition in a single story wood frame dwelling. Crews stretched and operated four lines and were hampered by an active natural gas leak. Mutual aid was provided at the scene by the Dix Hills Fire Department. The Kings Park FIre Department sent a unit to cover and Commack Ambulance sent numerous units to the scene. The fire was placed under control at approximately 1445 hours. Fire Marshals from the Town of Smithtown Department of Public Safety are investigating.