LAURENS, Iowa (AP) -- A flammable substance dumped into a residential sewer system caused several houses within two to three blocks of each other to have fires and associated problems, fire officials said.
Officials responded to a home shortly after 5:30 p.m. Tuesday and found a drain in the basement had burned. About the same time, a neighbor reported an undetermined odor in the basement. The home was vented.
Three blocks away, firefighters found a home in which a drain had released water and black material into the basement.
Shortly after flushing the sewer along the residential street, firefighters found a fire in a lower-level laundry room of another home.
The fires and related problems have been ruled accidental, said David Schipper, deputy state fire marshal.
``It is the opinion of the state fire marshal that something was possibly dumped into the sewer by someone and this product made it into the (affected) residences,'' Schipper said. ``This product vapor was ignited by a pilot light on a water heater in the basement... It is unknown who may have dumped a product into the sewer.''
Methane gas and natural gas have been ruled out, he said.
The incident remains under investigation.
