Rochester Fire investigators are ruling the fatal fire at an auto repair shop last week, accidental in nature.
Authorities say the fire was caused by a torch cutting operation that accidentally ignited flammable vapors which in turn ignited a flammable liquid.
Firefighters said the two-alarm fire started inside the commercial building on McKee Road and spread to the roof. The second alarm was called to bring in more manpower.
A man was found dead inside. The name of the victim is not being released.