Abstract: At 2:30 a.m. on July 4, 2021, an employee working as an oil well driller was working for a drilling company. The employee was tasking with using a pressure washer to clean the substructure of the drilling rig. The employee was on an elevated surface approximately 11 feet above the cellar. He reached over a guard rail to pickup excess hose for the pressure washer gun when the floor gave way and employee fell to the lower level. The substructure has four self-retracting lifelines and a fall protection harness available on the floor of the substructure. The fall protection harness was not being worn when the employee fell. The employee was hospitalized with two broken ribs and a fractured sternum.