Officials with the Office of the Ontario Fire Marshal have wrapped up their investigation at the scene of a barn fire that claimed the lives of 16 horses on Monday but they say they may never be able to definitively determine a cause.

OFM investigators spent most of Tuesday sifting through the rubble of Sunnybrook Stables after first arriving at the scene on Monday morning.

By 4 p.m., the investigation at the scene had been completed but OFM Investigator Chris ter Stege subsequently told CP24 that a cause could not yet be determined and could remain a mystery due to the fact only the charred rubble of the barn remains.

He said that there were reports of fireworks in the area on Sunday night and that an ember from those fireworks could have flown through an opening in the barn and ignited stacks of recently delivered hay inside.

But, he said that it is also equally conceivable that the fire originated in a trailer stored inside the barn or could have sparked by the electrical wiring in the structure.

“It is a theory but we have four other theories that could go along with it, so we can’t really prove or disprove it at this point due to the fact we have complete loss of the structure,” he said of the suggestion that fireworks were to blame. “Because we have multiple ignition sources that would be competent to ignite this barn we can’t really prove or disprove any single one.”

Ter Stege said that investigators have not found anything to suggest that the blaze was deliberately set at this point and are treating it as accidental.

He said that the investigation so far has suggested that the blaze began in the upper portion of the barn.

From there, he said, the blaze would have quickly spread due to the combustible nature of the structure.

“It was built in early 1900’s so there a lot of heavy timbre frame that had been drying for many years and we also had fresh hay that was recently delivered,” he said.

Fire was a ‘fully involved inferno’ by time crews arrived

Firefighters were first dispatched to Sunnybrook Park in the Leslie Street and Eglinton Avenue area for a reported grass fire at around 3 a.m. on Monday but when they arrived they found the main barn at Sunnybrook Stables completely engulfed by flames.

Toronto Fire Chief Matthew Pegg told CP24 earlier on Tuesday that the structure was a “fully involved inferno” and was “unfortunately gone” by the time crews arrived, so a decision was made to focus on preventing the fire from spreading to a second barn nearby.

He said that he “could not be more amazed and more proud” of the work that his crews did in preventing the further spread of the fire and ultimately rescuing 13 horses that were inside that second barn.

“Our command team made the decision that we would concentrate as many resources as we could on protecting the barn to the east. As you saw, it (the main barn) was a fully involved inferno and unfortunately it was gone. Our priority then was to prevent the spread of the fire and they did a magnificent job of that,” Pegg said.

At the height of the blaze, 16 trucks and upwards of 50 firefighters were on scene.

Pegg told CP24 on Tuesday that crews effectively “created a water curtain” to prevent the further spread of the fire. He said that allowed a group of firefighters and police to go into the second barn and rescue the horses inside.

Officials have not yet said whether they consider the fire to be suspicious, though Pegg did tell reporters on Monday that there were reports of fireworks in the area on Sunday night.

City working in ‘close cooperation’ with Sunnybrook Stables

Speaking with reporters at city hall on Tuesday, Mayor John Tory said that he is “still heartbroken” over the death of 16 “lovely animals” who were beloved by all those “who got to know them over the years.”

Tory also said that his office is working in “close cooperation” with Sunnybrook Stables in the aftermath of the tragedy, with the two parties having most recently spoken on Tuesday morning.

As part of that cooperation, he said that he has asked staff to look into whether another city-owned stable at Sunnybrook Park could be used by the operators of Sunnybrook Stables for lessons and summer camps.

“There is a building down there that was the former police stable that is empty and we are trying to figure out the status of that building and its condition and so forth so we can determine whether that is a possibility for this riding school to continue with its work at Sunnybrook,” he said.