Abstract: Employee #1 was on a pump jack scaffold when one of the multi-section aluminum poles supporting the unit collapsed. He fell approximately 24 ft, sustaining injuries that required hospitalization. Subsequent investigation revealed the following causative factors: 1) the aluminum poles inadvertently included defective components that had not been replaced or tagged/removed from service; 2) at least one of the secondary safety stops had been removed by a coworker prior to the accident because some pole sections had become stuck together that morning; 3) the scaffold had not been inspected by a competent person prior to use; 4) Employee #1 and his coworkers had not received site training relating to scaffolds and or been trained by a "qualified person;" 5) the poles had not been adequately secured to the building by rigid triangular bracing; and 6) only a partial guardrail system was in place.