I arrived on the scene of this Round Lake Beach house fire right behind the RLB Police. The family was already standing outside and it appeared the fire was contained to the rear bedroom, which had a O2 Tank inside it for a sick family member. Within 60 second of my arrival the tank exploded shooting flames sideways out the window and spreading the fire through out the home. Round Lake Engine 2622 arrived from Station 3 dropping a supply line from the main road down to the fire scene which was on a dead end street. By this time the fire had spread to several rooms of the home so firefighters had there hands full. Round Lake firefighters, assisted by a Grayslake Engine Company were able to extinguish the fire and keep it from speading to the west section of the home.