Abstract: On May 3, 2000, Employee #1 of Air Com Mechanical was injured during the performance of maintenance checks on a Con Tempo air conditioner, Model Number LEMX 2034, Serial Number 7993-1-2 J-90. The air conditioner was located inside the computer room at Toshiba, Inc. The air conditioner was being used to cool the large number of computers in the room. The computer was approximately 5-foot tall and 8 to 10-foot long. The air conditioner had a door that enclosed the belts and pulleys. When opened, a hole about 24-inch by 34-inch exposed the mechanical parts of the air conditioner. Inside are two belts on two separate pulleys. Employee #1 has been employed by Air Com Mechanical approximately 1 year. He has been doing repair work on cooling and heating units for more than 8 years. He did not receive any formal training from Air Com Mechanical on de-energizing machinery upon hiring. Employee #1 has attended safety meetings on Lockout and Tagout procedures and the company provides tags and locks. Employee #1 is an experienced cooling and heating repairman and was working alone. Employee #1stated that he shut off the control switch to the unit located inside the air conditioner. After verifying the equipment was off, he proceeded to inspect the belts and bearings. Employee #1 heard the machine come back on and his finger was caught in the belt and pulley abd got cut off. He made an attempt to de-energize the machinery but mistakenly disengage the incorrect switch, and was injured by the machine when it re-engaged.