Abstract: On May 26, 2010, Employee #1 of Safeway Services LLP., was dismantling a scaffold that had been erected inside a large boiler, which was part of a power generation plant. An unrelated company had used the scaffold to gain access to all areas of the inside walls of the boiler to clean them. The cleaning process produced a large amount of fine, dark-colored dust on scaffold parts and working platforms. As the planks and frames of each level of the scaffold had been removed, more of the dark-colored dust began to fill the air and settle on the scaffold planks below. By the time all but a couple of planks remained on the second to lowest tier, Employee #1 repositioned himself on the lowest tier in order to reach up and remove the two planks remaining above him. Since the lowest tier was protected by rails on the outside and the wall of the boiler on the inside, Employee # 1 believed it was no longer necessary to tie off. At this point in the operation, there was a lot of activity on the lowest tier with workers moving toward the area where scaffold parts were being handed down. There was also a lot of dust in the air which diminished the available light. Employee #1 was walking on the platform planks near the wall while moving to the drop-off point. Unknown to him, someone had removed two inside planks from that working platform and he fell through the hole to the floor approximately 20 to 25 feet below. Employee #1 was hospitalized due to his fractures.