Posted 27 Jun 2016
8 people died in the explosion
Steven Nanney, a senior engineer with the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA), said the law requires pipeline operators to review potential risks for pipelines in "high concentration areas" such as the San Bruno neighborhood where a PG&E pipe exploded in 2010. Nanney stated operators must maintain accurate records on repairs, defects, inspections and the physical attributes of pipes to adequately assess threats to pipelines.
"It's important to know the type of defect and attributes for assessing threats to the integrity of the pipe," he said.
Inaccurate listing
Federal prosecutors say PG&E inaccurately listed the San Bruno pipe as seamless, rather than welded, and was missing critical files on leak repairs for the line. That information is critical for calculating the maximum allowable pressure for pipelines and assessing risks in densely populated areas, Nanney said.
Grandfather clause
During opening statements Friday, a prosecutor told jurors that PG&E had a practice of spiking pressure on older pipelines up to 10 percent beyond the maximum allowed, and not conducting required tests on those pipes. For pipes installed before the Pipeline Safety Act was passed in 1970 — such as Line 132 in San Bruno — the law allows operators to set the maximum pressure at the highest pressure used on the pipes in the previous five years. That grandfather clause encouraged utility companies to spike pressure on older pipelines every few years to maintain higher capacities for pipelines, PG&E attorney Steven Bauer said during his opening statement.
PG&E has denied claims that it had a policy of spiking pressure up to 10 percent beyond the maximum allowed — despite a PG&E document that outlined the practice. PG&E said that document was merely a draft, not an official policy.
When the maximum pressure is exceeded on pre-1970 pipelines in densely populated areas, operators are required to conduct a pressure test or inspection to make sure the pipe is safe, Nanney told the jury Tuesday.
Cheaper external studies
But instead of conducting the more costly pressure tests, PG&E opted to perform cheaper external studies on those pipes, to maximize profits, Assistant U.S. Attorney Hallie Hoffman told jurors on Friday.
Nanney told the jury Tuesday: "A pressure test is the best way to check the integrity of the pipe." Nanney said external assessments like the ones PG&E performed were not an "appropriate assessment technology," which operators are required by law to conduct after exceeding the maximum pressure on older pipes.
PG&E could be considered experts on pipeline safety
On cross-examination, Bauer tried to discredit Nanney's status as an expert on pipeline safety laws. Nanney acknowledged he was giving his opinion on the regulations, not the official position of his employer, PHMSA, which is tasked with regulating pipelines.
"How do we go about ascertaining PHMSA's position?" Bauer asked. "You could submit an interpretation letter," Nanney said.
When asked if internal PHMSA training he took was necessary to become an expert on the law, Nanney said the training was helpful, but not necessary.
"That means people not at PHMSA could become experts at the code, right? Even experts at PG&E?" Bauer asked.
Nanney replied, "Yes," affirming Bauer's point that PG&E engineers could also be considered experts on pipeline safety laws. Nanney acknowledged that though the pipeline safety code spells out exactly what operators must do, it leaves room for engineers to use their own judgment to prioritize the greatest potential threats in the system. Nanney was expected to continue testifying Wednesday in the criminal trial, which is expected to last six to eight weeks.
PG&E could be fined $562 million
Before Nanney testified Tuesday, U.S. District Judge Thelton Henderson told the jury that the cause of the fatal explosion that on Sept. 9, 2010, killed eight people, injured 58, and leveled 38 homes is irrelevant to the case. "You will not be tasked with determining what did or did not cause the explosion."
PG&E is accused of 12 counts of violating the Pipeline Safety Act and one count of obstructing an investigation of the explosion. If convicted, it could be fined $562 million.