July 11— Seattle Fire Investigators are calling Friday’s fire at the high rise McGuire apartments in Belltown an accidental fire. Firefighters had to climb 25 floors to reach a fire on top of the soon to be demolished apartment building on Friday afternoon.

911 calls came in reporting thick black smoke coming from the roof of the building. Ladder truck 4 arrived first to find the 272 unit building covered with nylon sheathing. Within 15 minutes, firefighters found the fire confined to a mechanical room on top of the tower.

Investigators determined a spark from the construction equipment ignited the foam insulation on the roof of the structure. The dollar loss is zero because of the limited fire damage, and the fact the vacant building is set to be torn down.