Police say a natural gas pipeline ruptured and exploded into a huge fireball in northwestern Ontario, but no one was injured.

Greenstone Provincial Police Staff-Sgt. Carl Pettigrew said Sunday that the blast occurred late Saturday near Beardmore, Ontario, about 170 kilometers (105 miles) northeast of Thunder Bay.

Pettigrew says the flames were extinguished by Sunday morning.

Police say the section of the TransCanada Corp. mainline that exploded forced a few hundred people to evacuate their homes, but they were told shortly after that they could return home.

The Transportation Safety Board of Canada says they are investigating the cause of the explosion.