Abstract: At 4:30 p.m. on September 22, 2021, an employee working as a machine operator for a corrugated box manufacturer was troubleshooting a water leak in the Flexo folder/gluer converting machine. The employee was working with mechanics Coworker #1, the supervisor, and Coworker #2, a mechanic. The employee was required to be present to assist with limited authority while Coworker #1 and Coworker #2 performed their work. The employee was there to ensure the machine is operated properly for the maintenance crew to do their job. Coworker #1 and Coworker #2 had narrowed the area on the machine where the leak was likely occurring to the conveyor belt. They were trying to find the leak while the belt was still moving side to side in need of adjustment. The maintenance crew required that the machine be running to find the leak. After discussing the issues while standing in front of the machine, Coworker #2 told the employee to go shut off the water. The employee left the area and later the maintenance crew reported they heard his voice from the pit in the back of the machine under the conveyor. The door to the pit was usually closed and secured with a combination padlock. The door was left open so the maintenance crew could go access the area to work on the machine. The employee was not authorized to go in the back and enter the pit. The employee had entered while trying to find the leak. The employee tripped as he entered the pit and contacted the moving rollers and conveyor belt which caught his arm and face. The employee was aware of the restrictions and reported miscommunication with the maintenance team. The coworker was hospitalized to treat a broken right arm and laceration to his right cheek.