BILLINGS, Mont. — The Obama administration moved Wednesday to significantly expand a requirement for utilities to install inexpensive safety valves on gas lines across the U.S. following deadly fires and explosions going back decades that officials and safety advocates said could have been avoided.
The Transportation Department proposal would cover new or replaced natural gas lines serving multi-family dwellings, small businesses and homes not already covered under a 2009 mandate.
The National Transportation Safety Board and other safety advocates have pressed for years to broaden requirements for so-called excess flow valves. The devices cost about $30 apiece for residential use, according to officials, and are designed to automatically shut off the flow of gas when a line is ruptured.
An Associated Press investigation in 2012 uncovered more than 270 accidents dating to 1968 that could have been averted or made less dangerous if the valves had been in place.
Officials stressed that the valves won't prevent lines from being ruptured, such as when a backhoe doing excavation work slices through a gas pipe servicing a house. But by limiting the amount of gas that escapes, the valves can prevent a buildup of fuel that can contribute to explosions or fires.
"This important action will add extra protections to communities serviced by the nation's largest network of pipelines," Transportation Secretary Anthony Foxx said in a statement. He said the valves can have "a significant impact in reducing the consequences of natural gas leaks."
Federal transportation officials said if the valves had been in place they could have averted at least eight accidents that killed 10 people since 1998. Among those were a 2012 gas leak and explosion in Springfield, Massachusetts that injured more than 20 people and damaged dozens of buildings.
The valves also could help reduce emissions of greenhouse gases that are contributing to climate change, officials said.
As utilities across the country dig up their old, cast iron and plastic gas lines over the coming years, the rule would ensure they are replaced with safer lines that can be shut off more easily, said Carl Weimer, executive director of the Pipeline Safety Trust, a safety advocacy group.
"This will makes sure a lot of the older, most concerning pipes are taken out and replaced with lines that have safety valves," Weimer said. "That said, it won't do much good for existing lines that lack valves and aren't being replaced, so we would like to tackle that perhaps in the future."
The proposed federal rule would allow customers to request the safety valves for the tens of millions of gas lines already installed across the U.S., but does not specify who would pay for their installation.
About 180,000 automatic valves would be installed annually under the rule, according to the Transportation Department's Pipeline and Hazardous Materials Safety Administration.
Manual valves would be required for apartment buildings and large commercial or residential gas customers. The government projected that more than 40,000 of those valves would be installed annually.
Industry representatives have previously raised concerns about the potential cost of installation, particularly for larger gas lines that would require specialized valves. American Public Gas Association Vice-President John Erickson said utilities would be more accepting of a rule that is limited to smaller lines.
But Erickson added that quality control during valve manufacturing was crucial to make sure the devices aren't inadvertently tripped, shutting off the flow of gas for no reason.
"It's not going to affect every type of accident, but one where an excavator hits a service line, they seem to be effective at reducing the (gas) flow to where it's an insignificant risk," he said.
Installing the valves on new and replaced lines should cost between $4.4 million and $20.3 million per year, depending on the price of the valves, the Transportation Department said. Benefits from damages avoided were generally lower — between $7.3 million and $14 million.
Transportation officials said the proposal was nevertheless justified because of hard-to-measure benefits such as avoided evacuations, environmental damages and the possibility of a high-consequence incident that could inflict mass casualties.
The 2009 mandate required excess flow valves to be installed on new replaced gas distribution lines serving single-family residences. The proposal would expand that to include service lines serving multiple single-family homes, duplexes and other small multi-family buildings, and shops ranging from doctors' offices and shopping centres to banks.
The rule will be subject to a public comment period of at least 60 days. Federal officials said it could change based on the information received. No date for final adoption was offered.
Burke reported from San Francisco.
Matthew Brown And Garance Burke, The Associated Press