Abstract: At approximately 1:45 p.m. on March 8, 2013, Employee #1, an apprentice employed by Farwest Insulation Contracting, was part of a crew installing insulation to the ZLD Crystallizer Feed Tank on the Russell City Energy Center Project construction site in Hayward, CA. Her employer had been subcontracted by the general contractor, Bechtel. This work required working on scaffolding. Employee #1 was working on the second deck of the scaffolding, above grade, and helping Coworker #1 install insulation. The foreman, Coworker #2, was working on a level above Employee #1. Employee #1's immediate supervisor, Coworker #3, was working at another location on site and checking on Employee #1 approximately every 20 minutes, as needed. There was a large crew that day, with frequent supervision. Employee #1 was summoned to come down to ground level to assist. Upon exiting the gate at the scaffold rail, Employee #1 descended the ladder. At a level of approximately 8 feet above the ground, Employee #1 lost her footing and fell. She landed on her side, striking a standoff-supported 6-inch diameter pipe. The Hayward Fire Department responded to a call for emergency assistance and transported Employee #1 to the hospital, where she was admitted and treated for fractured ribs, a punctured right lung, and bruises to her right kidney and right leg. The Hayward Fire Department reported this event to Cal/OSHA at 9:20 p.m. on March 8, 2013, leaving a message with the Cal/OSHA Division's after-hours messaging service. The employer also attempted to report the event to Cal/OSHA but inadvertently called the local Federal OSHA office. A Cal/OSHA representative contacted the employer on March 11, 2013. The subsequent investigation found no obvious causal factor. Employee #1 was not carrying anything while descending the ladder, and the scaffolding and its ladder were observed to have been properly erected by Bechtel. The investigator's report concluded that Employee #1's injuries appeared to have been the result of a simple error in footwork.