The Helena Fire Department tackled a small residential fire on Tuesday morning.
No injuries were reported.
Authorities have not yet determined the dollar amount of damage.
Helena Fire Marshal Craig Trapp says that the initial investigation revealed that the fire may have been caused by a cigarette put out in potting soil.
Trapp says that this is the second fire within a month believed to be caused this way.
Trapp explained in a press release that potting soil is not the same as dirt, and is typically composed of shredded wood, bark, or peat moss mixed with minimal amounts of actual dirt.
Styrofoam pellets, perlite, and vermiculite are some of the other items that are often added to the soil mixture for aeration and water retention.
Many mixtures also include different types of fertilizers, some of which are oxidizers which will make a fire grow rapidly.
Trapp says that these fires typically occur on the outside of the structure in planters and pots.
Once ignition occurs, fire can spread to any nearby combustible such as a deck or the exterior of the structure.
Trapp says that firefighters have seen cases over the years where the fire is not noticed until it has progressed into the home or attic space. He says that those are the ones that can jeopardize the safety of the occupants and cause high-dollar losses.
Trapp recommends that if people smoke outside a home, they use a metal bucket or other non-combustible container with sand or water to extinguish their smoking materials.