A relatively inexpensive carbon monoxide detector could have saved the lives of five people in Whitehorse last week.

When firefighters entered the home of Bradley and Valerie Rusk last Sunday, their two children, 11-year-old Rebekah and 13-year-old Gabriel and fellow renter

Donald McNamee, the amount of carbon monoxide gas in the air was 10 times what would have been detected by a standard household machine.

It was that gas that killed them in their home in Porter Creek. They had no warning alarm.

The RCMP, Yukon coroner, fire chief and fire marshal held a press conference this morning to provide more information into the tragic deaths — the first of their kind in the city in 30 years.

Their bodies were found Sunday morning by a concerned friend. It is still unclear exactly when the deadly gas killed them.

"It could be any time from Thursday night to maybe Friday that it happened, and then they were discovered on Sunday,” said chief coroner Sharon Hanley.

Fire chief Clive Sparks said homes like the family's, built in the 1960s, do not legally require a carbon monoxide detector.

The alarms were made mandatory in residential homes when Canada's National Building Code was updated in 2005.

"For a building that age, they are not a requirement,” Sparks said.

"Anything that is built newer than about 2005 would require the alarms but in older buildings, it is not required.”

The RCMP have concluded their part of the investigation said, spokesperson Sgt. Don Rogers.

"At this point in time, we are confident that this is a tragic accident,” he said.

"If anything new comes to light, we certainly will examine that, but at this point, there is no grounds for a criminal investigation.”

The probe into the deaths is now in the hands of the coroner's office and fire marshal Dennis Berry.

Berry said his investigation is focusing on the house's heating system, which included a wood fireplace as well as an oil fire boiler system.

"This is obviously not a normal state of operations for any heating system,” he said. "The investigation is ongoing.”

The heating system was running when firefighters entered the home, Sparks said.

The fire marshal's office will eventually produce a report for the RCMP and the coroner's office.

As for who is responsible for maintaining the heating system in a rented home, Rogers said he could not comment on this case while the investigation was ongoing.

It may depend on the individual landlord/tenant agreement, he added.

Rogers said "recent” inspections were done on the heating system, but would no provide specific dates.

The family had been living in Whitehorse for four or five years and had roots in Alberta, officials said.

Fewer details were available on McNamee, who had been living in the city for about a year.

People with carbon monoxide poisoning can have such symptoms as dizziness, nausea and disorientation before eventually losing consciousness, Hanley said.

In the days leading up to their deaths, all five people appeared to have been feeling unwell.

"I can tell you that the children were absent from school the previous week, the family had been experiencing some illness, possibly flu-like symptoms, which maybe or may not be related to carbon monoxide poisoning,” Rogers said.

Both the children's schools and the parents' employers were told not to expect them that week.

McNamee, 47, had been in the hospital the previous week with an unrelated illness.

"If you take it into the context that all of these people had been experiencing known illnesses in the days previous to this. .. they may have associated any symptoms (of carbon monoxide) to the previous illness,” Rogers said.

Adding to the tragedy, officials agree, is if the deceased had kept going to work and to school, the fresh air would likely have helped clear their systems of the poison.

The last death from carbon monoxide poisoning in the city occurred about 30 years ago, Sparks said.

"From a safety prospective, certainly a carbon monoxide alarm in your home is going to help because it will warm you if the levels start to build up, and maintaining your heating system in good working order is also going to help.”

Full autopsies are not planned in this case, Hanley said, but blood from all five people is being sent to the toxicology lab in Vancouver for analysis.

See statement from the Yukon New Democrats in letters.