Abstract: At approximately 9:00 a.m. on February 24, 2000, two employees were working on top of the roof installing angle iron on a block wall. There was a 1-in. gap between the wall and the roof where the two employees were working. The angle iron was being attached so that sheet metal could be secured to the iron and the existing roof in order to close the 1-in. gap and to install a new roof. Two 2-in. by 4-in. boards were placed flat on the existing roof and ran to the wall to help support the iron being fastened. A 5-ft-9in. by 4-ft-8-in. hole was in the roof in close proximity to where the employees were working. The hole was covered up with two pieces of 3-ft-wide by 15-ft-long lengths of metal roof decking before the employees begun work. One employee left the roof to meet a grading contractor. Employee #1 attempted to position the 2-in. by 4-in. board next to the wall. The board could not be positioned properly due to hitting the end of the roof decking. Employee #1 lifted one piece of the metal decking and begun walking it back when he walked into the hole. Employee #1 fell 12-ft-11-in. to the concrete floor. Employee #1 sustained fractured ribs, a concussion, lacerations, abrasions, and contusions from the accident and was hospitalized.