Seattle gas explosion came from problem within home
The explosion that ripped through a house in northern Seattle and forced a neighborhood evacuation Monday was caused by a natural gas leak inside the home -- not pipeline leaks in the same neighborhood a day earlier, investigators have concluded.
A couple badly injured during the blast and subsequent fire had smelled gas in their home Sunday -- the same day utility workers were checking out three pipeline leaks just blocks away -- but had not reported it, Seattle Fire Department spokesman Kyle Moore said in an interview.
"The couple that lived there said they smelled natural gas yesterday, but they also had some other odors, so they did not know if it was natural gas or not. They did not report it," Moore said. "This morning they woke up and started turning things on -- and boom."
The explosion was caused by an electrical spark igniting gas inside the house, he said.
Authorities said it was merely a coincidence that there were three leaks in a natural gas pipeline serving the neighborhood the previous afternoon, an incident that also forced the evacuation of some houses.
In that case, investigators believe that electrical arcing -- most likely caused when wind toppled a tree into a power line -- caused three separate holes in the underground pipeline, Martha Monfried, spokeswoman for Puget Sound Energy, the local utility, said in an interview.
She said lightning might also have caused the arcing, which sent a damaging surge of electricity through the pipeline, enough to break it in three places.
"Things go to ground. Whether the line touched the ground, [electricity] found its way into our pipes. They're steel-wrapped pipes, and steel does like electricity," she said.
-- Kim Murphy
Photo: Seattle firefighters work to extinguish a blaze in the aftermath of a gas explosion on Monday. Credit: Ted S. Warren / Associated Press