Abstract: On January 6, 2011, Employee #1 was working for a concrete contractor as a concrete worker. Employee #1 was working on the ground beside a three story building under construction. Employee #2, an employee of the framing contractor constructing the building, cut sheet rock covering a window opening with the intention of opening the window frame for the glass. Employee #2 could not see Employee #1 working below the window opening. Employee #2 notified employees working on the ground at the side of the building that overhead sheet rock removal was taking place. Employee #1 was not visible at his work position, so he did not receive the notification that work was going on above his work position. Employee #2 cut the sheet rock and as he began to remove it, a corner broke off. The piece of sheet rock fell to the ground and struck Employee #1 on his hard hat. Employee #1 was not seriously injured, but he did suffer a mild concussion.