Abstract: Employee #1 and a coworker were measuring the distance of a purlin from a platform that was located outside the guardrail system on top of the roof of the precipitators. The coworker was positioned on the platform and Employee #1 was positioned on the purlin above where the measurement was to be made. Both were tied off when in position but not while moving to the desired location. After the measurement was taken, the coworker turned around and got over the guardrails to get to the top of the roof of the precipitators. Employee #1 straddled the Wall Wind girt and slid down, facing the beam with his back to the guardrails. When he was stepping back to climb over the rails, Employee #1 stepped on a pvc pipe that was part of a discontinued water line. The pipe was not sound enough to carry the employee's weight, and Employee #1 fell 62 ft to his death.