The Yukon fire marshal says the carbon monoxide poisoning of five Whitehorse residents in January was accidental, but the report points to some big problems with their home’s heating system.

The fire marshal's report says the chimney was falling apart and parts of the furnace had not been properly installed in the rented home of Brad and Valerie Rusk, their two children and friend Donald McNamee.

The masonry chimney was crumbling and there's no sign of a metal liner supposedly installed inside the chimney in 1991. Bits of masonry that had fallen inside contributed to the chimney freezing over and blocking the vent.

The report also says faulty installation of a replacement boiler also contributed to the frozen chimney. It notes that much of the work on the heating system had never been permitted or inspected.

Ed Lockington, a close friend to the Rusk family, said he appreciates the fire marshal's office’s thorough investigation, including photographs of the frozen chimney.

"I was really surprised at the damage," he said. "The chimney itself being frozen down to a less than three quarters of an inch hole in the middle -- that's shocking, shocking."

Lockington said one relief is that everybody, including those in the furnace servicing industry, wants to make sure a similar tragedy will never happen again.

Coroner Sharon Hanley says the fire marshal's report will form part of her final report.

"That's one part of our investigation and there are more investigative reports I am gathering and we don't have those completed as of yet," she said.

"So until I have all the information gathered and have time to put it all together, we'll be waiting for the report until that's accomplished."  

Hanley has not decided yet whether to call an inquest into the deaths.

Opposition politicians are renewing their demands for a public inquiry into furnace safety following a weekend fire which happened in the boiler room at the Stratford Motel in Whitehorse.

They say the government was warned on many occasions about a lack of regulations and inspections for the oil heating industry. NDP Leader Liz Hanson says the motel fire is just the latest furnace-related incident and one that should have been avoided.

However Community Services Minister Elaine Taylor says she's going to wait a while longer before taking any action.

"The government of Yukon is waiting for the coroner’s report into this tragedy."

Taylor said the government has also set up a working group of furnace safety and expects it to report within a matter of weeks.