By Paul Rogers, Mike Rosenberg and Neil Gonzales Bay Area News Group
Posted: 09/11/2010 11:44:04 AM PDT
Two days after a massive pipeline blast engulfed a Peninsula neighborhood in a hellish inferno, search teams made the grisly discovery of three more bodies in a home destroyed by the explosion, and new information surfaced about a 2008 sewer project that could have weakened the gas line.
In all, the death toll rose to seven, and six additional people are still considered missing, officials said Saturday night.
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In one potentially significant area for investigators, records surfaced Saturday showing that two years ago, the San Bruno City Council hired a construction company to replace underground sewer lines in the same area as the location of the pipeline that exploded.
In May 2008, the city approved a contract with D'Arcy and Harty Construction, a San Francisco firm, to replace 1,670 feet of aging sewer pipes on Earl Avenue from Sneath Lane to Glenview Drive. The sewer work crossed the gas pipeline at the intersection of Earl and Glenview, which is the location of the explosion.
To avoid the disruption of digging trenches in the street, the contractor used a method called "pipe bursting." Crews pulled a large cone-shaped device through the aging 6-inch sewer pipes, shattering them, and replaced them by pulling a new 10-inch polyethylene sewer pipe in behind them. The technique can cause ground shaking and disruption of adjacent soil and rock.PG&E spokeswoman Geisha Williams, asked by a resident Saturday at the town hall meeting about whether the sewer work could have damaged the natural gas line nearby, said that PG&E inspected the gas line before and after the sewer work, and found no problems.But a representative of the California Public Utilities Commission, which regulates PG&E pipelines, told the Mercury News that large transmission pipes, which move gas at high pressures, can be at risk of failure if they are damaged, even in relatively small ways.
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