Portland Fire and Rescue’s Arson Squad said Monday that gas leaked into the basement of the building at 500 NW 23rd Ave. that exploded after an excavator struck a steel gas line.
"The contact pulled the pipe out of a fitting that was further underground, which started the release of natural gas," a press release from Portland fire officials said. "The natural gas then traveled under ground near the pipe and entered the basement."
The people injured in the explosion include three firefighters, two police officers and three civilians.
Because electricity was still on in the building at the time of the explosion, investigators said they weren’t able to determine exactly how the gas ignited.
"Due to the number of possible electrical and other ignition sources in the basement, fire investigators are classifying the specific ignition source as unknown at this time," the release stated.
