Abstract: At approximately 1:50 a.m. on January 31, 1990, Employee #1 was inspecting the rotary airlocks on the dust collecting systems on a roof. He would stop the airlock, remove the access door, and shine a flashlight into the duct to visually inspect the seals on the rotor vanes. Employee #1 pulled a switch on the SR5 unit and climbed 8 ft to the access door. When he removed it, he saw tobacco dust puffing out, indicating that the unit was still running and that, unlike other units, it was wired into a second switch that had not been turned off. As he started to climb down to pull the second switch, Employee #1 slipped on some damp tobacco dust. When he grabbed for a flange with his left hand, four of his fingers went over the flange and into the rotor, shearing off their tips. Employee #1 was hospitalized.