Abstract: At approximately 9:40 p.m. on August 10, 1998, Employee #1, a supervisor and operator in the sanding department, observed excessive sawdust coming out of one of the sanders, indicating a problem in the dust collection system. After checking the sanding unit, Employee #1 went to inspect the baghouse dust collection system outside the main mill, on the east side of the facility. Employee #1 was standing on the top step of a wooden stepladder to access the 6 ft 3 in. high top of the dust collector frame. He was about to shake the air relief bags when there was an explosion in the cyclone-baghouse dust collection system. Employee #1 was thrown back from the top of the baghouse frame and struck a pallet of cardboard boxes before falling to the ground. He sustained a concussion and a sprained right knee, and was transported to Lakewood Regional Hospital in Lakewood, CA.