Gas explosion may stem from weld failure

SAN BRUNO, Calif., Dec. 15 (UPI) -- A welding failure is suspected of causing the San Bruno, Calif., gas pipe explosion, an early federal report said.

The interim National Transportation Safety Board report found Pacific Gas and Electric Co. did not know the 54-year-old segment of the underground pipe that ruptured Sept. 9 even had a seam weld along the spine, the San Francisco Chronicle reported.

After the blast and fire that killed eight people and wiped out 37 homes, PG&E turned in maps and charts showing the 30-inch pipe was seamless, the NTSB said.

Federal law requires gas distributors to identify risks to lines and tailor inspections to them. PG&E inspected the pipeline last year, but with a technique that experts say cannot spot bad welds.

Richard Kuprewicz, a pipeline safety engineer in Redmond, Wash., said PG&E's ignorance of its own pipeline "calls into question the whole process" it used to maintain it.

PG&E's vice president for pipeline operations, Kirk Johnson, said executives took the discrepancy "very seriously and are doing an exhaustive search of our records" to make sure they are accurate.

But he said federal regulations do not distinguish between pipes with seams and those without when mandating inspection techniques.