California Public Utilities Commission lawyers blasted PG&E for its use of salvaged pipe in an Oct. 19 filing and accused the company of knowing about faulty seam welds dating to 1948.
The reuse of salvaged pipe has also come under scrutiny by the National Transportation Safety Board, which is investigating the San Bruno incident that killed eight people in September 2010.
The commission's legal department said PG&E documents that show reuse of salvaged pipe "raise serious safety concerns both for the future and for past safety, including the causes of the San Bruno pipeline rupture.
"The National Transportation Safety Board (NTSB) has been unable to certify the provenance of the ruptured pipe, or whether any pups that made up the pipe had previously been used elsewhere in PG&E's system. Moreover, we believe that PG&E cannot accurately certify that no other re-used and/or deficient transmission pipe remains in service."
Four records show that 2,500 feet of 24-inch-diameter pipe in Palo Alto/Stanford was moved starting in 1957. But none indicate the disposition of that pipe, besides the 22 feet that was reused.
A Jan. 1, 1957, construction drawing indicates that Line 132, which was the gas main that exploded in San Bruno and runs down the Peninsula, was relocated along Page Mill Road between Junipero Serra Boulevard and El Camino Real.
Regarding the 22 feet of reused pipe, PG&E wrote in its Oct. 20 response to the Utilities Commission that the pipe in Palo Alto dates from 1947.
"PG&E is hydro testing this section of pipe this year," the company wrote.
Last Friday (Nov. 4) PG&E announced that crews performing hydro tests near Palo Alto found a leak that is estimated to be about 1 millimeter in diameter. It is not known yet if the leak is located in the reused portion of pipe.
The 4-mile hydro test area contains nearly 21,000 feet of 24-inch seamless pipe that was installed in 1947. About 2,700 feet has a seam weld and was installed in 1957, PG&E said.
On Tuesday, crews determined that that leaking pipe was located on Page Mill, under the eastbound lane, between Hanover Street and Peter Coutts Road. One lane was blocked Tuesday as crews dug the pipe out; testing and repairs were scheduled to proceed Tuesday and Wednesday, according to spokesman Brian Swanson.
PG&E in its reply to the California Public Utilities Commission said that the reused, salvaged pipe and the issues pertaining to the 1948 welds are not new to PG&E or the industry.