The explosion was apparently caused by a defective battery, and was so powerful that it caused the battery to shoot out of the device, hit a piece of furniture and set it on fire, Joseph Miller, chief of the local fire department, told dpa.
"The device was burnt and melted beyond recognition," he said.
The man has spent the past several days in the hospital since Monday's accident.
The electronic cigarette is a replacement for the traditional cigarette, and allows the user to get a nicotine fix by inhaling a mist that tastes like tobacco smoke. Many e-cigs are shaped to resemble actual cigarettes.
According to the lobby organisation Tobacco Vapor Electronic Cigarette Association (TVECA), 2.5 million people in the United States use the product, although it is not currently regulated, according to TVECA's chief executive Officer Ray Story.//DPA