Abstract: At 2:40 p.m. on July 19, 2017, Employee #1, a roofer trainee/helper, and Coworker #1, a foreman, both employed by a construction company, were engaged in roofing repair and replacement at a two-story single family residence. They were installing roofing tiles over an underlayment of tar paper installed by another work crew. Toward the end of the work day, preparing to finish work at the instruction of Coworker #1. Employee #1 walked away from Coworker #1 and toward a Werner 24-foot extension ladder placed along the roof's eve. Before he could climb down from the roof, Employee #1 slipped on the tar paper and fell down to the concrete surface, a fall height of 17 feet. Emergency services were called, and Employee #1 was transported to the hospital. He was admitted and treated for multiple fractures of his hip, wrist, and both knees that required surgery. The subsequent investigation determined that Employee #1 had not received training on slip and fall hazards of working on underlayment during very hot weather.