Long before a leaky gas line erupted into a deadly inferno in San Bruno, Piedmont officials worried that they know too little about the web of pipes under city streets. Friday, after seven months of pressing the utility, the city got the promise of some answers.
In a morning meeting at city offices, PG&E officials showed the city a map of the gas lines within city limits and said it would give city the information it contained, eventually.
"This is something that could be critical information for us to make better," said Piedmont Fire Chief Edward Tubbs.
But the utility didn't commit to a date by which it would provide the information, and it is asking the city to keep the information confidential.
"We're providing a map of the gas distribution network to the Public Works Department and the first responders, but we are also working with them to observe proper security," said PG&E spokesman Joe Molica.
He noted that individuals can—and should—find out whether undertaking any digging project is likely to intersect with a gas or other underground utility line by calling 811.
Although he wasn't sure when the information would come, or in what form, City Clerk John Tulloch said the city representatives left the meeting satisfied.
"It was nice that they came and they assured us that they want to share with us as much information as they could."
Piedmont originally contacted PG&E March 16 because city workers had noticed inaccuracies in the reports that the utility gives before construction projects. The city would like to add PG&E's lines to its geographical information system (GIS), which comprehensively maps sewage and water lines and other aspects of the city's infrastructure.
"We have had instances where PG&E has incorrectly marked the location of gas lines, which could have caused a problem had our contractors not exercised a high level of caution based on their experience," Chester Nakahara, the city's interim director of public works, wrote in a follow-up letter.
"We aren't currently authorized to give out GIS data for a number of reasons, including safety and security," wrote Elizabeth Proctor, a PG&E GIS group supervisor, responding to Piedmont's initial request in a May 4 e-mail.
Other communities around the Bay Area began pushing PG&E to reveal more information after the Sept. 9 fire, which apparently started in a 30-inch-wide transmission line, killed eight people and incinerated 37 homes.
Separately, the Alameda County Fire Chiefs Association—of which Tubbs is a member—is also pushing for more details about the transmission lines.
Transmission lines are like the arteries of the gas circulatory system; they feed a network of capillary-like distribution lines leading down streets and into buildings. Most of the utility's response to requests for information has focused on transmission lines and valves that could be used to shut them off in an emergency.
PG&E has assured Piedmont officials that there are no transmission lines within the city limits. And it has offered further information about transmission lines to the public through its web page, www.pge.com, and through a map on the National Pipeline Mapping System site. It has also identified a "Top 100" list of locations on transmission lines that it plans to review more closely.
Tubbs said transmission lines matter to the Piedmont Fire Department because it might be called to help fight fires elsewhere in the Bay Area. And the transmission-line maps PG&E has provided so far aren't detailed enough, he said. And he looks forward to knowing more about the distribution lines as well.
"It would be really nice to know where those are," he said. "There were issues in the Loma Prieta earthquake where distribution lines were snapped. I've got to believe that there were homes that survived the earthquake, but because of gas lines, that home was destroyed."