State pipeline safety regulators said an improperly abandoned gas line caused the March 9 natural gas explosion that injured nine firefighters and destroyed several businesses in the Greenwood neighborhood.
The Utilities and Transportation Commission staff report said the line, which was owned by Puget Sound Energy, had been abandoned since 2004, but had not been properly disconnected and sealed. The line was located in a space between Mr. Gyros and Neptune Coffee in an area that was not intended for occupancy, but that was used as an unauthorized storage space.
People using the space disturbed the gas line, eventually causing it to fail, the report said.
The commission has filed a formal complaint against PSE alleging the company committed 17 safety violations and recommended a penalty of up to $3.2 million.
PSE said in a tweet that it is reviewing the findings of the investigation.
The complaint will be heard by the three-member commission. The commission is not bound by its staff recommendations.
Staff also recommended that PSE review all previously abandoned service lines to make sure they were in compliance with safety regulation and to identify any problems.