By Keith Lacey
A malfunctioning natural gas furnace that spit flames and ignited some clothes on a basement clothesline appears to have caused a deadly house fire in Hanmer 16 months ago.
Dave Scott, who operates his own Toronto-based fire investigation service, testified Tuesday at a coroner?s inquest. It is Scott?s opinion some corrosion near the burners of a natural gas furnace caused a build up of gas, which burst into flame when it was finally ignited by a pilot light.
The gas then burst through a small opening at the front of the furnace and ignited a large amount of clothes hanging from a basement clothesline, said Scott.
In earlier testimony, two experts from the Ontario Fire Marshal?s office agreed the scenario described by Scott was a probable cause of the fire, but would not categorically agree with his findings.
Scott was testifying at the inquest into a deadly house fire 16 months ago at 4141 Roy St. in Hanmer. Asha-Jade McLean, 3, her brother Ellias McLean, 4, and their great-grandmother Pearl Shaw, 75, perished in the fire.
All three experts agreed the fire started in the basement near the furnace; it was likely clothing caught on fire and eventually the heat and fire became so intense it burned away an entire section of the main floor.
All three bodies were found near each other in the basement after the flooring in the main floor bedroom and closet burned away.
Because of some corrosion near the pilot light on the furnace, there was a build up of gas and the gas likely flew out of the front end of the furnace once it finally ignited, Scott testified.
The build up of gas spit out through a cavity in front of the furnace and ignited the clothing, said Scott.
?We know we had the potential for delayed ignition?the pilot light didn?t ignite right away,? Scott testified. ?That was the most probable cause of the ignition source we could find.
?The scenario was perfect for that situation to occur.?
Testing of interior furnace components, a natural gas water heater, natural gas lines inside and outside the home, and electrical panels were all eliminated as potential causes of fire, said Scott.
The investigation confirmed the clothesline stretched across the entire basement was full of clothes at the time, said Scott.
Other garments were also piled on a nearby set of shelves and those clothes likely caught on fire as well, he said.
During a normal fire, a small portion of ceiling leading upstairs would burn away and move the fire vertically, but in this particular fire a huge section of basement ceiling and main floor flooring disintegrated at a slow pace, said Scott.
?A very large area of the basement was burning at the same time,? he said. ?I?ve only seen this happen four or five times? in the 500 residential fires he?s investigated.
The only logical explanation for the fire pattern is all the clothing on the clothesline caught on fire and burned for an extended period of time, which caused the ceiling and floor to eventually collapse, he said.
?In my opinion, the fire progressed by the clothing,? he said. ?The degree of charring was virtually the same across the entire basement.?
This particular fire was in a ?glowing or smothering state? until it burned away that section of the main floor and was then accelerated by sudden bursts of oxygen, said Scott.
That?s why he believes the fire burned for 20 to 30 minutes before neighbours noticed the fire once it expanded to the attic and roof, he said.
Several windows were knocked out by desperate neighbours trying to get in to save the children, the inquest has heard.
Unfortunately, breaking the windows provided a burst of oxygen which fuelled the fire and advanced a smouldering blaze heavy with smoke to raging flames, probably within seconds, he said.
It was his opinion it took more than 20 minutes from the time the clothes caught on fire for the floor to eventually burn away and collapse, he said.
Dan Newburn, a fire investigator from the Ontario Fire Marshal?s Office, testified he was called to the scene the day the fire took place.
After the bodies were recovered, he returned to the scene the next day and took fire debris to assess the origin and cause of the fire, he said.
?Most of the damage was in an area around the furnace area,? he said.
The fire definitely started in the basement, burned away the flooring of the main floor bedroom and closet area before proceeding to the upper areas of the home, he said.
He agreed the children and Shaw were likely in the main floor bedroom or closet, which eventually burned away, causing them to fall to the basement.
?Most of the fire damage on the main floor was right under the closet,? he said.
Investigators found two smoke alarms on the main floor, but could not tell if they were working properly at the time, Newburn testified.
Qadeer Choudry, a fire protection engineer with the fire marshal?s office, testified he examined the water heater, a fireplace, kitchen area and agreed the fire started in the basement near the furnace.
He also noticed corrosion near one of three burners on the furnace.
He also agreed there would likely be a build up of natural gas if the pilot light doesn?t immediately light burners when the furnace is turned on.
?There was corrosion on the pilot light and I wanted to examine what role the corrosion might have played,? he said.
In his professional opinion, natural gas could have caused a build up and rolled out to the front of the furnace, but in his final report he wrote down ?undetermined? as the cause.
?In our business, we do not deal probabilities, but we deal in absolutes,? he said.
After his full investigation, Choudry said he was not prepared to make a determination that a natural gas malfunction caused the fire.
The inquest before a three-woman, two-man jury is expected to last all of this week and early into next week.
