Sherman Fire-Rescue investigators have determined that a discarded cigarette left behind by a tenant likely started a fire that damaged dozens of self-storage units last week.

Division Chief and Fire Marshal Danny Fuller said crews were dispatched to the Devon Self Storage complex in the 1700 block of Loy Lake Road shortly before 9 p.m. last Thursday after receiving reports of heavy smoke and flames coming from the facility. Fuller said no injuries were reported, but the fire started in a single, central unit before it spread outward in both directions and damaged more than 65 units. By Friday, Fuller said he had determined that the male lessee had visited his unit prior to the fire and failed to extinguish either ash or the remaining cigarette butt he left.

“He was smoking and the best determination we can come up with, right now, is that he didn’t get rid of the ashes properly,” Fuller said Monday.

The marshal said a couch inside the man’s unit was the first object to catch fire. Fuller said the flames spread over a period of more than 15 minutes before the fire was noticed by passers by and called in, but could not be more specific. He said the initial delay and the logistics of accessing dozens of individual storage units made for a more complex offensive against the fire.

“With that many doors and locks, it impedes the access somewhat,” Fuller said Friday. “We have tools and equipment to breach those, but we always try to approach it in a way where we do as little damage as possible.”

Fuller said employees of the storage facility estimated that the fire caused approximately $500,000 worth of damage. However, Fuller said no criminal charges would be filed against the man.

“It’s an accidental (fire),” Fuller said. “There doesn’t seem to be any indication of it being intentional.”

A representative of Devon Self Storage reached by phone Monday said employees could not comment on the matter.

Fuller said Sherman Fire-Rescue crews have seen an increase in the number of preventable cigarette-related calls in the last two to three years. Residents of the Travis Lofts in downtown Sherman were evacuated in early April, after a cigarette butt left in a window well briefly caught fire and a resident of the Lone Star Inn and Suites was killed in November after a cigarette-like product caught bedding materials inside her room on fire.

“People should be using some type of metal can or drown them out in some kind of water,” Fuller said of discarded cigarettes. “Any small cigarette butt that has any tobacco in it at all can cause a fire. Sometimes, it can even be as long as a couple hours later before it gets going. It just holds the heat for a long time and displaces that heat into other items, that you might not even think about.”