Deer Lake fire Chief John Dinney said an unattended wood stove was the cause of the blaze, which started just before 4 p.m., as the owner stepped out to run an errand.
The flames gutted the large shed, which contained several washers, dryers and other appliances, as well as a bicycle and some electronic equipment. The items were strewn across the ground as firefighters tore the structure apart to get at the fire.
Dinney said the firefighters were informed that a smaller shed next to the larger structure contained barbecue propane, meaning firefighters had to be careful to soak the shed thoroughly and get the tank out to avoid an explosion.
The smaller shed was not damaged.
The blaze occurred on a day when firefighters were scheduled for training exercises.
There is no estimate as to the financial loss, and no one was hurt.
Dinney said the incident is an example of what could happen when a wood stove or fireplace is left unattended. He advised those using fire to heat their homes to use caution, especially during the extreme cold temperatures the area has been experiencing.