Abstract: At approximately 9:15 a.m. on August 24, 2002, Employee #1, the operator of the #2 boiler at a cogeneration plant, and a coworker were unclogging an ash dump hopper. Initially, they prodded the congested area with a pipe through a clean-out hole with no success. Then they secured the power to the mixing auger, which was below the hopper, and checked for a clog. As Employee #1 reached up into the area around the rotary valve at the bottom of the hopper, four of his fingers on his right hand were amputated. Emergency services were contacted and Employee #1 was transported to Sutter Roseville Medical Center, where first aid was provided. He was then transferred to Ralph K. Davies Hospital in San Francisco for hospitalization and further observation. During the accident investigation it was revealed that the rotary valve had not been deactivated; there were separate control panels for the two pieces of equipment, and neither Employee #1 nor the coworker had locked out both machines.