Abstract: Employees #1 and #2, both apprentice carpenters, were on a house scaffold with aluminum painter's planks, installing 16 in. wide horizontal masonite siding. They were unable to reach the top three or four rows from the scaffold, so they put two 6 ft stepladders atop the free-standing scaffold with the ladder tops leaning against the building. Employee #1 climbed a ladder to work. Employee #2 started to hand him a section of siding when the scaffold/ladder combination jackknifed, throwing both workers to the ground. Employee #1 was diagnosed with a possible ruptured spleen and intestinal damage. He underwent exploratory surgery and was hospitalized for 5 days. Employee #2 sustained cuts and bruises; he returned to work the next day. The accident resulted from using an illegal scaffold.