YB had worked in the construction industry for many years. He had his own company, and was a subcontractor on a major project involving the construction of a multistory parking garage. Preparation was in progress for pouring concrete to create another level. While waiting, he saw that there were some sheets of plywood on the floor. YB went over to where one of the sheets was located. Apparently, he was not aware that the sheet of plywood covered a hole. In the process of lifting the plywood sheet, he stepped into the opening and fell through the floor onto the concrete pavement below. YB died as a result of the injuries that he sustained in the fall.

HF Issue: Why did this accident occur, especially in view of YB's years of experience in the construction industry?

HF Investigation: Considerable time had elapsed between the accident and my investigation. I relied on accident and medical reports, the depositions of witnesses, as well as on photographs and diagrams of the parking structure.