By Bill Kirk
ANDOVER — A gyser shot about 20 feet into the air from a high-pressure natural gas main for nearly four hours yesterday after a construction crew installing a sewer line on River Road accidentally struck the plastic pipe, officials said yesterday.
As a result, four homes located at the intersection of River Road and Cross Street were evacuated, roads in the area were shut down, electricity was turned off to nearly 700 customers, gas service was temporarily halted to 260 more customers, and school buses had to be re-routed.
Among the customers to lose power was the Wood Hill Middle and High Plain Elementary schools on High Plain Road. Among the 260 customers who lost gas service were the 121 apartments at Avalon Andover, an apartment complex near the Tewksbury line.
Columbia Gas crews attempting to fix the pipe were thwarted in their efforts to stop the leak because they were unable to turn off a valve that controlled the flow of gas in the area, according to several officials at the scene.
A spokeswoman for the gas company said the valve had been erroneously paved over and was inaccessible from the street.
As the gas continued to spew into the air, people living farther away from the scene began to complain of the odor of gas in their homes as well. Fire officials went house to house at one point, testing the air quality of the homes as some people were afraid to re-enter their dwellings.
The leak was finally shut off after gas company crews used a device to crimp the plastic pipe, stemming the flow of gas, at 4:22 p.m. The leak was first reported at 12:30 p.m. by a firefighter on scene who was directing traffic as part of a private detail, according to Fire Chief Mike Mansfield.
Columbia Gas spokeswoman Andrea Luppi said the problem was caused when a contractor excavating a trench for a sewer line hit the pipe.
“Our line was exactly where it was marked out to be,” she said, referring to spray-painted marks on the road surface put there by Dig Safe. “It was marked. It was the contractor laying the sewer line.”
She said the main reason it took so long to stop the leak is that there were a number of steps the company had to take first.
“We had to wait for the contractor to move their equipment,” she said. “We had to wait for the electricity to be shut off. We had to locate the valve, which was paved over.”
She said the valves are “not supposed to be paved over. It should be visible and should be accessible.”
Once they determined it was covered, Columbia Gas crews then excavated near the leak and “squeezed off the pipe” to stop the flow of gas, she said.
The contractor doing the work on the sewer line is MDR Construction Co. Inc. of Tewskbury. A message was left on their voicemail last evening at about 5 p.m.
MDR is excavating a trench that is 17 feet deep in places as it installs about 890 feet of new sewer line under River Road, according to David Dargie, a construction inspector for the town of Andover.
He said the gravity-fed sewer line is being installed along River Road from the intersection with Cross Street down to a new road called Jillian Way, which is under construction. The four-lot subdivision is also under construction.
Dargie said he couldn’t say what happened.
“The Department of Public Utilities is on-scene investigating it,” he said. “I can’t say what went wrong yet. I will not do any finger-pointing at this time. It’s still being determined” who’s at fault.
He said the pipe, made of plastic, was installed in the trench “fairly recently” although he couldn’t say exactly when.
Because of the location of the pipe, he said the sewer line may have to be re-engineered before work can get underway at the site, hopefully early next week.
Gas company crews were expected to work late into last night and into the morning hours today making sure that all the homes in the area would get their service restored.
Luppi said that restoring service is a multi-phased process, starting with going house to house to shut off the gas and speaking with residents to make sure all their appliances are off.
Once the line is fixed, crews have to go from house to house again to turn the gas service back on. However, they need to gain entry to every single dwelling to get all the appliances re-lit.
Electricity was shut to the nearly 700 homes in the area as a precaution, as safety officials didn’t want there to be any possible causes of ignition, such as a spark or an electrical arc, that could ignite the natural gas.
Schools were notified that bus routes had to be altered. Mansfield said one of his main concerns was ensuring that buses could get to all of their stops so that students wouldn’t have to walk too far to their homes. He said the school department and police worked out a plan to make sure the buses got to all their regular stops using alternate routes.
One parent called The Eagle Tribune to complain that the school was not informed it would be losing power.
Mansfield said that the school adapted and came up with alternate activities for the kids and then released them at the regular time.
Electricity was restored to the area by around 5 p.m.