Middletown was dispatched to a car fire in the area of Walmart around 10:30 am. Rescue 27 and ambulance A-1 arrived to find an engine compartment on fire on Merrimac Avenue next to the Walmart. The crews were extinguishing the fire when the bumper shock exploded and struck a firefighter, injuring his leg. He was treated and released. Units on scene: Rescue 27 & Ambulance A-1 with Captain Herrman in command.