Abstract: On May 24, 2012, Employee #1, the Facilities Manager for a furniture manufacturing company, was cleaning and unjamming a screw conveyor system that serviced the shop dust collection system. Employee #1 had been advised earlier that morning that a water curtain spark arrest system that had been fitted to the baghouse-type dust collection system had tripped, causing the conveyor troughs to become clogged by a water/sawdust slurry. The company had fitted light sensors to the system as part of the spark prevention system, and Employee #1 was informed by another manager that one of the sensors had become caked over with slurry, preventing proper operation of the system. Employee #1 stated in an interview on September 14, 2012 that he went to the main power supply panel and activated the emergency power stop button, but he did not lock the handle of the power main feed supply and maintain custody of the key. Employee #1 then instructed two employees to stand next to the main power supply panel and make sure no one turned the power on. Employee #1 could not recall who the two employees were. Employee #1 then located the area of the sensor fault and removed a cover, exposing the auger conveyor. Employee #1 initially reached in with his right hand and started to wipe the sensor lens clean. Not being able to accomplish this with his right hand, he then reached in with his left. Employee #1 cleaned the sensor lens, and once it became clear the auger started up, pulling his left arm into the auger, and amputating the arm. Employee #1 then went to coworkers, who attended to him. Employee #1 was then transported to Harbor USC Hospital in Torrance, California.