A defective piece of heated metal hardware "was a factor in this accidental and devastating fire," LaMont Keen, the utility's chief executive officer, told a news conference.
"To the extent we are found to be responsible," Keen said, "we will fulfill our obligations."
Several events played a role in the wildfire, including the loose piece of hot metal that fell from the utility pole to the ground and ignited the blaze, according to investigators. Also contributing were high winds and an additional electrical current caused when a tree fell into power lines shortly before the fire.
The Boise Fire Department, Idaho Power and the federal Bureau of Land Management participated in the investigation.
The fire was reported around 7 p.m. August 25 in a vacant field of sagebrush and dry grasses. Winds gusted up to 50 mph and within two minutes the blaze had spread to a nearby ridge and roared toward a line of homes in a Boise subdivision, Fire Chief Dennis Doan said.
"This was a terrible accident caused by high winds," Doan said.
Fire officials have said 10 homes were destroyed.
After the blaze was brought under control fire crews discovered the body of Mary Ellen Ryder in a house that was destroyed. Ryder, 56, was a professor of English and linguistics at Boise State University and Boise police have determined she was likely a victim of the wildfire.
Idaho Power owns the land beneath the utility line where the fire started. The piece of equipment that malfunctioned is called a connector and it was last inspected in 2006, said Lisa Grow, the company's vice president of delivery engineering and operations.
"These types of devices rarely fail," Grow said. "It's quite rare."
Idaho Power, the state's largest utility, routinely inspects power lines every three years, Grow said. "The loose connector would have not been visible even if an inspector saw it the day before the fire," she said.
Earlier this year, fire crews helped residents in the Boise neighborhood where the fire occurred clear "defensible spaces" around their homes, urging them to cut down sagebrush and dry grasses.
But fire prevention measures proved futile against the fast-moving winds, which carried the fire to the line of homes overlooking the ridge, and then continued onto houses across the street.