A water heater tank exploded and blasted through the roof of a video store in Burien, WA. The tank hurtled across a busy intersection and over six lanes of traffic before landing over 400 feet away in the parking lot of a pizza shop. The tank then tumbled another 25 feet before coming to rest.
Four people were injured in the blast. Three were treated and released from a local hospital, but one woman was admitted to a medical center with second-degree burns to her arm. The powerful blast occurred Saturday morning July 28 at a small strip mall in the Seattle suburb.
![[picture of exploded water heater tank]](inspection-photos/expolodedwatertank.jpg) | |
Puget Sound Energy workers look over the remains of the water heater tank in a parking lot in Burien, a block away from the video store, where the tank was before it exploded on Saturday.
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Initially, the blast was thought to have been caused by natural gas, but an investigation quickly ruled that out. Authorities said a plumber had been in the building the day before the blast. The battalion chief of King County Fire District 2 said, "The pressure relief valve had been capped, and the tank was partially drained of water, it built up steam pressure, it was a steam explosion."
Water heaters are equipped with pressure-relief valves. The valves are designed to open immediately to relieve pressure if steam builds up in the tanks. Although rare, pressure explosions of water heaters have occured. In 1993, a 40-year-old 200 pound water heater exploded and shot through a floor, ceiling and roof like a missile, at a home in South St. Paul, Minn. The explosion shot the tank 150 feet in the air. It destroyed the home, slightly injured two people and killed the family dog.
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| | The back wall of the video store was blown out. |
The Burien, WA explosion blew off the front of a video store and spewed shattered glass across the parking lot. It also blasted a hole through the cinderblock rear wall of the building. A woman who owned the video store suffered the worst injuries. Witnesses said she was covered with dust and had bad burns on her arm. On the other side of the alley from the strip mall in an auto glass store, an employee was getting ready to install a windshield when there was a "whoomph" sound followed immediately by intense pressure. Blown to the floor, the glass installer said, "I turned and saw everything flying at me." His manager, yelled for him to get out of there. The area where he had been standing was littered with shards of glass and chunks of concrete blasted from the strip mall wall. He was shaken, but not injured.