Overpressurized lines caused deadly gas explosions, feds say

LAWRENCE, Mass. (AP) — Federal investigators are confirming overpressurized natural gas lines were the source of the deadly explosions and fires in communities north of Boston last month.

Thursday's preliminary report from the National Transportation Safety Board says Columbia Gas workers failed to account for the location of critical gas pressure sensors in Lawrence on Sept. 13. It caused high-pressure gas to flood a low-pressure distribution system at excessive levels.

The excessive pressurization led to more than 80 explosions and fires across Lawrence, North Andover and Andover that killed one person and injured 25 others. The gas explosions also damaged or destroyed dozens of homes, and left thousands of homes and businesses without natural gas service.

Joe Hamrock, president of NiSource, Columbia Gas' parent company, said the company can't comment on the incident's cause until the investigation is complete.