Abstract: On June 10, 2005, Employee #1was leaning down, walking backwards, while stapling weather barrier paper to an exterior wall, while the wall was laying flat on the second floor of a single family home under construction. The exterior wall was approximately 12 ft by 20 ft, with openings at the top and bottom. The two openings were approximately 5 ft by 6 ft, and approximately 5 ft by 6 .66 ft. The bottom wall opening was not supported, and overhung the unguarded edge of the second floor balcony by approximately 3 ft. The openings in the weather barrier paper for the windows were to be cut out after the application was completed. Employee #1 stepped on the weather barrier paper covering the bottom wall opening, fell through the weather barrier paper, and through an unguarded floor hole on the first floor, which measured 37.25 ft by 4.66 ft to the basement, for a total of 21 ft. Employee #1 sustained a back injury. He was not trained in OSHA fall protection requirements, nor was he using a fall protection harness, or guardrails. He was not hospitalized for his injury.