They likely thought the fire in the ceiling was small and under control.
Then it killed them.
North Perth firefighters Ray Walter, 30, and Ken Rea, 56, had a few seconds' warning that the roof above their heads was engulfed in hidden flames ready to fall on them March 17, 2011. Other firefighters saw the flames and got out, but they didn't have time.
Now, fire chiefs across the province have been told to use "extreme caution" when faced with fire in ubiquitous, single-storey commercial buildings like the Dollar Stop at 245 Main St.
"We are going to use the real world tragic circumstances here and the physical evidence to add to our existing training program," said Chris Williams, a senior Ontario Fire Marshal's office senior investigator who probed the blaze.
"It really drives home the horrifying circumstances of losing one of their members."
Roofers using a propane torch started the fire in the 25-year-old building. Flames quietly grew in a false ceiling for 40 minutes before smoke was spotted and firefighters arrived. Flames exploded out of the hidden space 19 minutes later as the weakened structure collapsed.
The fire marshal's office is pushing fire commanders to be wary of plain concrete block buildings. They may have hidden areas between the interior ceiling tiles and the roof where flames can grow unseen, consuming wooden roof trusses. There are about 100 commercial and public buildings in the municipality of 14,000 people Smith wants to fully inspect now.
Hiring an inspector to do pre-planning might be discussed by town council next year. First, all the investigations into the fire must be completed, including a Ministry of Labour probe, Smith said.
The Dollar Stop fire acted in ways firefighters didn't expect, Smith said. His crews will be much more wary of such buildings in future.
The building frustrated firefighters using a thermal imaging camera trying to find the flames. The sensor couldn't pick up heat through the ceiling tiles because of insulation, Smith said.
Fire Marshal investigator Williams refused to second-guess the actions of firefighters that day in Listowel. He knows now about the roofing work earlier in the day; firefighters didn't know the fire had so long to grow.
He knows about the hidden, 1.5-metre high space between the ceiling and roof. Firefighters didn't. Nor could they see dangerous flames because so much smoke was trapped in the space. That smoke exploded as fresh air rushed in while firefighters poked through ceiling tiles searching for the heart of the fire.
"It's really difficult to apply information we learn from hindsight to the conditions and experiences at the front end," Williams said.
"Every particular incident is going to be a challenge to the fire service. It's a very hazardous profession."