Abstract: At 10:59 a.m. on January 9, 2020, Employee #1, employed by a school district, was working underneath a bus at the bus barn. He was attempting to perform a repair on a stuck RUD Rotogrip L171 automotive snow chain system, model number 69798. He was struck by and pinched underneath the school bus by the swivel arm of the snow chain system. The arm had inadvertently moved. He was killed by asphyxiation by being trapped between the snow chain system and the floor. Later repair information revealed that the electrically operated air control solenoid for the Rotogrip L171 snow chain system was defective.