Yellowknife (May 13/05) - Two Yellowknife firefighters killed in a warehouse blaze were caught under falling debris that crushed their chests and prevented them from breathing, according to preliminary autopsy results.

Firefighters Kevin Olson (above) and Cyril Fyfe (below), who died in March battling a warehouse blaze in the industrial section of Yellowknife, were asphyxiated by fallen debris according to preliminary autopsy results.

Cyril Fyfe and Kevin Olson were buried under the rubble of a five-metre-high storage shed that collapsed March 17.

The weight of the debris pressed down on their lungs and prevented them from inhaling - a condition known medically as compressional asphyxiation, said Chief Coroner Percy Kinney.

"Even if their air supply was functioning properly, they could not breath in," Kinney said Tuesday.

Fyfe was a long-time Yellowknife resident and 18-year veteran of the fire department. Olson, 24, had been working at the department for less than a month.

Drew mourners

Their deaths shocked the capital. Memorial services for the fallen officers drew mourners from across Canada and the United States.

Clues have begun to emerge surrounding the cause of the deadly blaze, which engulfed the interior of a metal storage shed at the Home Building Centre on Old Airport Road.

Deputy Fire Marshall Steve Moss said the fire does not appear to have been intentionally set, though he cautioned that determination could change.

Chuck Carruthers, owner of the renovation centre, said investigators examined an electrical heater and wiring inside the shed. Moss confirmed a heater was sent to a southern laboratory for examination, although it was too early to determine whether it triggered the fire.

Completed within a month

A final report from the fire marshall's office should be completed within a month, he said.

The Royal Canadian Mounted Police and Worker's Compensation Board are also conducting their own investigations.

Several questions surrounding the tragedy remain unanswered. Kinney said it could be several months before his office issues a final report on the incident.

"There is a wealth of information," Kinney said. "There are no quick answers. I don't know if we will ever have the full picture."