Abstract: Employee #1 was part of a concrete finishing crew that had started working at a job site in the morning. His company had contracted to have a concrete boom pump on site. The driver of the pump truck had modified the pump hose before it was put into service. Employee #1 picked up the end of the hose; a coworker (his foreman) was 6 to 8 ft behind him, holding the hose. The concrete was being pumped into the modified hose when a stoppage occurred. Suddenly, the concrete shot out of the hose and the foreman lost his hold. The hose ripped out of Employee #1's hand and hit him in the chest, bringing him to his knees. It then whipped back, striking him on the neck, head, and shoulder, and rendering him unconscious. He sustained injuries requiring hospitalization.