Abstract: At approximately 10:00 a.m. on September 15, 2010, an employee was working for a firm that installed windows, glass, and doors at commercial and residential buildings. The employer had been hired to install windows and a door at a single-family dwelling. The employee was working as a window installer for the employer, and he did not have any supervisory responsibilities. On the day of the accident, the injured employee was approaching a window opening. As he walked toward the window, he accidently stepped in an opening in the floor made for an HVAC vent. The opening was 24 inches long, 6 inches wide, and approximately 21 inches deep. The employee lost his balance and fell forward toward a windowsill. His hand and arm were cut by broken glass. He sustained an 8-cm laceration with muscle avulsion to the left upper extremities. Paramedics were called, and the employee was transported to Cedars Sinai Medical Center for surgery and medical treatment.