Abstract: At approximately 2:00 p.m. on September 25, 2013, Employee #1 was performing cleaning using compressed air on a concrete pumping truck with a boom. As the cleaning sponge was fed through the boom piping on the truck using compressed air, the cleaning sponge jammed in the pipe and then released forcefully through a section of piping that had been removed to discharge the sponge. The employee's hand was struck by the sponge as it discharged from the piping. Employee #1 was transported to U.C. Davis Hospital, where he was underwent surgery to repair multiple fractures to the right hand and a partial amputation of the right ring finger. The employee was hospitalized over twenty-four hours.