Monroe Firefighters handled a post fire investigation Saturday morning. A homeowner called in to report they had heard an explosion in the middle of the night and when they woke up, found a contractor’s equipment pile had burned up.  Firefighters found a painter’s equipment had likely naturally combusted and caused a flash fire that burned various materials and shrubbery. Due to smoldering conditions firefighters overhauled and wet down the area. The incident is under investigation by the Fire Marshal and the state Department of Energy and Environmental Protection.