The cleanup of what is left of homes destroyed in the San Bruno gas line explosion will begin today.
The goal is to remove the debris of the homes and other materials burned in the explosion and subsequent conflagration before the rainy season. The fear is rain may wash toxic material into the Bay.
The Sept. 9 blast, which was caused when a Pacific Gas & Electric natural-gas line exploded, killed seven people, injured dozens more and razed at least 34 homes. Left behind in the destruction was rubble and ash that could contain toxins, such as material from paint cans, batteries and vehicle oil.
Homeowners, who are responsible for the cleanup of their property, can choose to sign up for a county program or pay for the removal.
San Mateo County is working to have the homeowners use a single contractor, allowing work to be done in a systematic way, according to Dean Peterson, director of the county’s environmental health division.
So far, 25 of the 36 owners of the red-tagged homes have signed up to have the county haul the remains of their homes to the landfill, he said. Others have been reticent to sign up, not yet ready to let go of the only evidence of their former lives, he said.
“These are individuals who less than two weeks ago lost everything they have, and to fathom that all of everything that is left is going to be put into a bin and hauled away is difficult for some of them,” he said.
The entire cost of the cleanup is estimated to be between $1.75 million and $2 million, according to the county, which is working with owners’ insurance companies to recoup costs.
The cleanup process ran into a speed bump when the Bay Area Air Quality Management Board said that all of the rubble had to either be treated as asbestos waste, or extensively tested for the toxic material — either of which Peterson feared would drive the cost of cleanup so high that the project would have to be delayed into the rainy season.
A compromise has been reached where the county agreed to treat ash as potentially contaminated by asbestos, but large chunks of cement and metal can be removed without testing.
PG&E reveals some gas line locations
Pacific Gas & Electric bowed to pressure this week to release the whereabouts of underground pipelines carrying natural gas, but the list isn’t complete.
The location of natural-gas pipelines has become a focal point after the explosion and conflagration in San Bruno on Sept. 9 that killed seven people and incinerated dozens of homes.
Pressured by regulatory agency California Public Utilities Commission, PG&E created a website that reveals approximately where the transmission lines are, and a hot line for residents to call to determine whether they live within 500 feet of one. But the company had refused to disclose the location of gas distribution lines.
For instance, a 24-inch gas line runs through the Financial District, up through Chinatown, through the middle of The City near Golden Gate Park and out through the Sunset district. Despite the size, however, it is not on the map of pipelines that PG&E released.
The difference in the type of lines has resulted in a web of large pipelines throughout the Bay Area whose locations and size residents have no right to know. While federal code mandates utility companies provide information about transmission lines, there is no such mandate about distribution lines.
PG&E spokeswoman Nicole Liebelt said a transmission line is intended to carry large amounts of natural gas long distances, whereas distribution lines disperse them through a city. Most distribution lines are small mains that run down many streets, only a few inches in girth. But in large population centers, the distribution lines can be as large as 24 inches in diameter, she said.
The technical difference between the lines is the pressurization. A transmission line is highly pressurized — a 24-inch pipeline can carry as much as 375 pounds per square inch. A distribution line is limited to a load of no more than 60 pounds per square inch, Liebelt said.
Because of the pressure difference, transmission lines can be more dangerous, according to Carl Weimer, executive director of nonprofit Pipeline Safety Trust. He said, however, that a distribution line failure can cause major damage as well, particularly in densely packed neighborhoods.
“Most [distribution lines] are operating at a low enough pressure that if it fails, you’ll get a leak, not a rupture,” Weimer said. “Certainly, leaks can be dangerous, and they blow up lots of houses, but you won’t get the big rupture that will take out an entire area, like we saw in San Bruno.”
Nonetheless, he said, the public has a right to know where the distribution lines are — though clarifying exactly where the high-pressure transmission lines runs should be the priority.
“Federal regulations have been focused on [revealing where] high-pressure transmission lines are — but there’s not any requirement that anybody produce the maps of the distribution lines,” he said.