Abstract: At 7:15 a.m. on August 11, 2020, an employee working as a laborer for a plumbing contractor was performing work for a residential construction project. The employee is a full-time employee of the employer. Coworker #1, senior plumber, assigned the employee to work with Coworker #2, another plumber, installing gas pipes in the basement. The employee was setting up the pipe threader machine in the basement. Coworker #1 was at the store picking up construction materials and Coworker #3, the site lead, was working at a different construction site. The employee and Coworker #2 and another coworker were walking around the basement looking for a piece of cardboard or plywood to place underneath the pipe threader machine in order to protect the floor from oil stains. They walked between 10 to 20 feet from the location where they wanted to place the pipe threader to a corner where wood pallets, cardboard, and plastic were left by other contractors. The materials impeded the employee's ability to see a piece of plywood that was covering a floor opening. The employee stepped onto the plywood which was not vaulted down to avoid displacement. The employee fell through the opening and fell about 8 feet onto the concrete floor in the basement. Coworker #2 and the other coworker had turned their back for a moment and did not see employee fall and initially did not hear him scream. Eventually, they realized what happened and went to the employee's aid. The employee was hospitalized to treat serious injuries to his back, neck, face, shoulders, knees and arms and was discharged on August 13, 2024.