Abstract: On October 25, 2007, Employee #1, an ironworker/helper and two coworkers were assessing the work to be done to move a 2,400 lb dust collector vessel on the fifth level of a newly constructed coal mill tower. The vessel had been previously placed on the edge of the planked floor opening cover while it waited for fit-up further in on the fifth level. Employee #1 walked over to the vessel and out on to the cover for a 58 in. square floor hole when one 2 i., by 10 in. scaffold-grade plank gave away, followed by two more planks. Employee #1 fell 44 ft onto a building rooftop, then bounced and fell another 13 ft to the ground. Employee #1 was killed. Subsequent investigation found that none of the floor opening scaffold planks broke. Failure of the hole-cover was caused by the planks being unsupported on one end due to displacement over the hole. The hole cover was not secured to prevent accidental displacement nor labeled with the required warning, "Opening-Do Not Remove."