WINNIPEG -- Many of the 4,000 residents of southeastern Manitoba affected by a natural gas pipeline explosion proved to be creative and resilient as they entered a third day without heat Monday.

Steve Cope was using an electric fireplace and two portable space heaters to keep his two-storey home in Niverville warm as the temperature outside dipped to near -30 C.

"One (space heater) we've got actually facing the cold-air return on our furnace, so it's kind of blowing that air into that cold-air return. And we have the fan running on the furnace so it's kind of circulating throughout the house," Cope said.

TransCanada PipeLines vice-president Karl Johannson said the company hoped to have natural gas service restored to everyone by midday Tuesday. He suggested some communities could have gas back by Monday night.

There were no reports of injuries from the fiery blast, but Johannson apologized and promised that the company would cover any direct losses people experienced.

"We are sorry the impact this is created," he said. "We are doing everything we can to restore natural gas services from our pipeline so that your homes and businesses can enjoy the heat that they rely on, especially during this type of cold weather."

He thanked neighbours for helping each other by sharing space heaters and offering accommodation.

Patrick Guenette, his wife and two children spent Saturday night with his parents in St. Adolphe before he managed to borrow and buy a total of five space heaters. The family was back in the home Sunday.

"Considering it was 14, 15 (degrees) the other day, hovering around 19 is OK," he said.

Municipalities in the region south of Winnipeg had set up warming centres on the weekend for people who were no longer able to stay in their homes, but the centres were virtually empty.

The Rural Municipality of Hanover set up shelters in two communities and only had one person visit.

"It's great news because it means people have been very self-sufficient," municipality spokeswoman Heather Chambers Ewen said.

The explosion happened at a TransCanada valve site near St. Pierre-Jolys early Saturday. It sent a huge fireball into the sky and forced the temporary evacuation of several nearby roads. Crews isolated the line and the flames were extinguished by Saturday afternoon.

Johannson said the line that ruptured was a 76-centimetre, tar-coated pipe that was installed in the 1960s. Its last thorough inspection was done in 2009 and it was in "very good condition."

Crews were working around the clock to restore gas supplies, but were battling extreme cold. Johannson said there were 100 workers on site and another 200 off site working on the problem.

Limited supplies of natural gas were being trucked to critical locations such as personal care homes.

RCMP have said the cause of the explosion is not suspicious. The Transportation Safety Board was investigating.

Safety board investigators were "documenting and preserving evidence of the rupture," said regional senior investigator Jerry Berriault.

"We're going to be doing a full investigation into this incident, but at this point we're just in the field phase," he said.

Johannson said it was too early to say what went wrong.

"We simply do not know at this time. It is going to take time before we can figure out the cause."