House leveled when gas ignites
It will probably take days before the cause of the explosion in an empty home is determined.
October 2, 2007
SOUTH PORTLAND — Investigators are trying to determine why an unoccupied building apparently filled up with gas before an explosion leveled the house and shook nearby buildings Monday morning in the Knightville neighborhood.
"We have moved from the operational stage to the investigation stage," Robb Couture, a spokesman for the South Portland Fire Department, said Monday night. "We are focused now on determining a cause, how the building filled up with gas, and what the ignition source was." He said the investigation could take days.
Concerned residents, meanwhile, asked why they were not evacuated an hour before the explosion, when workers installing a water main broke a separate gas line under D Street, next door to the house that later exploded.
The blast happened around 9:40 a.m. It destroyed an unoccupied, two-story rental property at 43 D St. and shook houses and office buildings throughout the nearby area. Officials evacuated most of Knightville between A and Market streets, which included dozens of homes and businesses.
Workers spent several hours looking through the rubble before finding and capping the ruptured line around 3:15 p.m. Most residents were allowed to return home by Monday night, except those who live along D Street.
Phil Notis, a member of the trust that owns the destroyed building, said contractors had been preparing the house to be rented.
"It's unbelievable. We were about ready to rent," Notis said. "We're very fortunate that no one was working."
His brother, Alex Notis, said he had no idea what could have ignited the explosion in the unoccupied house, which was built in 1890 and had an assessed value of $102,000, according to city records.
"We're dumbfounded. It was vacant. Everything was shut off," he said.
About a week ago, Risbara Bros. Construction, a contractor hired by the Portland Water District, started work to replace a water main beneath D Street. Neighbors said workers had dug up portions of the street several times in recent years to fix leaks in the pipe.
Around 8:25 a.m. Monday, a worker using a backhoe clipped an underground gas line that ran from the street to a yellow house at 47 D St.
It was not clear if that line had been properly marked, or if the worker simply made a mistake. Sheila Doiron, a spokeswoman for Northern Utilities, said her company marked the street to show the location of pipes before any digging, which is done under the multistate Dig Safe System.
Risbara workers plugged the broken line and notified Northern Utilities and the South Portland Fire Department, which is standard procedure for any gas leak. Employees of Northern Utilities began checking nearby residences for any problems.
Bryan Davis of 55 D St. said a Northern Utilities employee knocked on his door and used a meter to take a gas reading in his basement.
"They said one of the construction workers had nicked the pipe," Davis said. "They had a meter, and they said my house was fine."
Someone from Northern Utilities also contacted Central Maine Power Co. and asked that electricity to that area be turned off. But the gas utility provider called back to say the move was unnecessary, said CMP spokeswoman Gail Rice.
"They told us they needed us, then they told us they didn't. So we held off," Rice said.
Doiron, of Northern Utilities, said workers usually check door- to-door for gas levels whenever there is a leak. She said she did not know whether they were able to check the unoccupied house that exploded.
"That's still under investigation. We're still trying to get the details," she said.
Procedure dictates that three structures on either side of the leak are checked for gas levels, Doiron said. When there's no access to the inside, a plunger bar -- a tool about 5 feet long and a quarter-inch in diameter -- is driven into the ground to get the reading.
The so-called six-point check was in progress when the house blew up, Doiron said.
Because the leak caused by the backhoe was contained, and gas levels were normal at nearby properties, no one was evacuated, and South Portland Fire Engine 8 left the area around 9 a.m., Couture said.
About half an hour later, people in the neighborhood heard and felt what they thought was a bomb.
"The whole building shook, and debris was falling down in our building," said Sarah Rawlings, an employee with Volunteers of America, an organization in the building next door.
Rawlings and her co-workers raced out and saw the wreckage of 43 D St., recognizable only by the black shingles of its roof atop a mound of debris.
The blast tore the fire-escape stairs off the Volunteers of America building, which also has four apartments on the second and third floors. Rawlings said at least one person had been on those stairs earlier in the morning.
After the explosion, Rawlings recalled seeing the fire truck earlier, and hearing men outside talk about a gas leak. On Monday night, she questioned why more was not done to protect public safety.
"They should have evacuated people" when the leak was discovered, Rawlings said. "They let people remain in the adjacent buildings. I think that is irresponsible."
She was not sure whether she and co-workers would be allowed to return to work today, or if they would even want to return.
"Frankly, I don't really feel safe," Rawlings said.
Couture said gas leaks are routine occurrences, and most do not require evacuation. The one known leak Monday morning had been plugged, and it was in the open air, out on the street where the gas could dissipate, Couture said.
Investigators want to know if the explosion was related at all to the backhoe incident, or whether the line to 43 D St. was damaged before Monday morning.
It's possible that the line was broken during road work in the past few days and gas had filled the basement, said South Portland Fire Chief Kevin Guimond. Investigators also still do not know what sparked the explosion.
"We're going to find out," Guimond said. South Portland has been joined in the investigation by the state Fire Marshal's Office, Northern Utilities and the Maine Public Utilities Commission.
Power to the area was cut off by CMP after the explosion. Doiron said she had no indication that the blast had anything to do with electric service.
The PUC will look into two areas: whether safe digging procedures were followed, and whether there was a problem with the piping system. Preliminary reports are not expected to be completed before next week, said Fred Bever, a PUC spokesman.
In April, a house equipped with both propane and natural gas exploded in Portland's West End. Although the explosion was caused by a flammable vapor, it's not yet clear which substance was the cause, said Portland Fire Chief Frederick LaMontagne.
Also in April, a pressure surge in a natural gas line led to leaks, two fires and the overnight evacuation of 300 residents from a Saco neighborhood. The PUC issued a notice of probable violations after concluding that Northern Utilities could have prevented the surge. Settlement talks are under way, Bever said.
Doiron said gas leaks can be caused by a variety of factors, from building renovations to equipment installation to aging infrastructure. She said the kinds of leaks that could result in an explosion are not common, but didn't have any figures on their frequency.
"Problems that result in what happened today are, very fortunately, rare," she said.
Staff Writer Trevor Maxwell can be contacted at 791-6451 or at: