Canada officials use controlled explosion to fight train derailment fire

A large fireball rises from the site of a train derailment in New Brunswick, Canada, Friday, Jan. 10, 2014 as officials used a controlled explosion to blast holes in three tanker cars in the hopes of fighting a large fire that continues to burn two and half days after the incident. Canadian National Railway spokesman Jim Feeny says the procedure they used is known as vent and burn, and preliminary indications are that it went according to plan. (AP Photo/The Canadian Press, Kevin Bissett) (The Associated Press)

A large fireball rises from the site of a train derailment in New Brunswick, Canada, Friday, Jan. 10, 2014 as officials used a controlled explosion to blast holes in three tanker cars in the hopes of fighting a large fire that continues to burn two and half days after the incident. Canadian National Railway spokesman Jim Feeny says the procedure they used is known as vent and burn, and preliminary indications are that it went according to plan. (AP Photo/The Canadian Press, Kevin Bissett) (The Associated Press)

A controlled explosion was used to blast holes in three tanker cars of a derailed oil train in an attempt to extinguish a large fire that continues to burn two and half days after the incident, a Canadian National Railway spokesman said Friday.

A large fireball shot into the sky and a boom resounded after the blast.

"Preliminary indications are everything went as planned," said Canadian National spokesman Jim Feeny.

Officials said 19 rail cars in the 122-car train derailed Tuesday night in a sparsely populated region roughly 20 miles (32 kilometers) from the U.S. border and northern Maine. No one was injured, but about 150 people living nearby were evacuated. There is no word yet on when they might be allowed to return to their homes.

The controlled explosion, known as vent and burn, was used on two tanker cars carrying liquefied petroleum gas that were burning and a third one with the gas in it that was not on fire, Feeny said.

Canada's Transportation Safety Board's lead investigator Guy Laporte said earlier this week that a crack in a wheel near the front of the train caused the wheel to loosen from the axel, resulting in the derailment of that wheel set. But Laporte said it's too early to determine what caused the train to leave the tracks.

The incident again raised concerns about the increasing use of rail to transport oil throughout North America. In July, 47 people were killed in Lac-Megantic, Quebec, when a train carrying crude oil derailed and exploded in the middle of a small community.

A number of recent derailments in North America have worried both officials and residents close to rail lines. On Dec. 30, an oil train derailed and exploded in North Dakota, causing the evacuation of a nearby town but no injuries.