PUTNEY -- At just past 8 a.m. on Sept. 2, all four lanes of Interstate 91 were shutdown between Exits 4 and 5 due to a leaking propane tank.
According to a press release from the Vermont State Police, the cargo tank tractor, operated by Osterman Propane of Whitinsville, Mass., had pulled into the weigh station in Putney on southbound I-91 for a commercial vehicle safety inspection check.
Lt. Kevin Andrews, of the Enforcement and Safety Division of the Vermont Department of Motor Vehicles, was inspecting the tractor trailer when a fitting in the pump used to load and unload the propane from the cargo tank failed, resulting in the release of approximately eight gallons of propane, or liquid petroleum gas.
The cargo tank was loaded with 8,300 gallons of propane.
Andrews told the Reformer he was just crawling out from under the tanker when the fitting on a fill pipe gave way.
"I've never seen that fitting give out," he said. "It was nothing that could have been anticipated. If not at the scale house, it would have happened five miles down the road."
If it had begun to leak while the vehicle was in motion, said Andrews, there's no telling how long it might have been before the driver noticed.
"Once the propane changes from liquid to gas there is a white plume. Depending on how much came out and how much the driver was paying attention, going down the road at 65 mph, a leak would have been hard to detect.
The leak was in a filler pipe, said Andrews, at the bottom of the truck, where gas is forced into the tank. There is a stop valve between the main tank and the filler pipe, said Andrews.
"It's closed during transport, but in the grand scheme of things, there is on the off chance if it's not working properly you run the risk of having 8,300 gallons coming out."
"We weren't so much concerned about an explosion as we were an uncontrolled gas leak," said Putney Fire Chief Tom Goddard. "If we had had a significant gas leak, that would have involved shutting down the highway for several hours, and we know the ripple effect that has on Route 5."
In addition to the Putney Fire Department, personnel from departments in Guilford, Westminster, Brattleboro and Walpole, N.H., responded to the scene. The fire departments were assisted by the Vermont State Police. The Vermont State Hazardous Material Response Team assisted a private contractor in sealing the leak so that the tanker could be driven to Bellows Falls where the propane was offloaded at a storage facility.
The fire departments were placed on standby in case water flow was required to disperse any gas, said Goddard.
"That would have involved a tremendous amount of mutual aid to supply continuously flowing water."
Because the leak occurred in open air, Goddard said there was no danger of asphyxiation.
There were no injuries or environmental impact from this incident. The load had originated in Claremont, N.H., and was headed to Sunderland, Mass. The highway was closed for approximately two-and-a-half hours and the commercial vehicle safety inspection check point resumed operations at 10:45 a.m.
Bob Audette can be reached at firstname.lastname@example.org, or at 802-254-2311, ext. 160. Follow Bob on Twitter @audette.reformer.