State fire investigators say they are focusing on propane as the likely cause of Tuesday morning’s deadly house explosion in Bath. Maine Department of Public Safety spokesman, Steve McCausland, says propane was the only fuel source for the duplex, and was heated by gas heaters. The explosion happened around 5am on Bluff Road. McCausland says a woman was killed in the explosion, her name has not yet been released. Four other people, including neighbors were taken to hospitals with minor injuries.