Abstract: At 1:30 p.m. on October 5, 2020, Employees #1, #2, and #3, employed by a precast concrete and structural steel company, were installing precast concrete stairs for a new 15-story commercial building, a multi-employer construction project. They were on the 13th and 14th floors and adjusting the stairs for proper elevation. The employees were using a 20-foot webbed sling and two 3-ton chain hoists. The stairs below the 13th floor had been installed, including necessary welding. The stairs on the 13th and 14th floors were not yet welded or secured. The employees were in the process of adjusting the stairs for proper elevation when the 14th floor staircase collapsed and hit the 13th floor. This caused all of the stairs directly below to collapse as well. The three employees, who were tied off to the staircases, were pulled down with the collapsing concrete, which had a total weight of approximately 75,000 pounds. The employees and concrete fell down the staircase shaft, a fall height of approximately 150 feet. Employees #1, #2, and #3 were all killed.