Abstract: At 2:43 p.m. on August 11, 2020, an employee was working as part of a four-person crew to deliver and transport roofing material to a jobsite. The employee and a coworker were working on the rooftop of a grain milling warehouse facility, using a four-wheel steel utility cart to transfer rolls of TPO roofing membrane, weighing approximately 150 to 200 lbs per roll, to another area of the roof. The roofing materials were loaded onto the rooftop by a mobile crane. As the crew were moving the cart across the rooftop, a coworker who was pushing the cart from the back, had bent down to retrieve a roll of TPO roofing material that fell off the cart. However, the employee continued to pull the cart from the other end, and momentarily turned his back into the direction of travel. The employee tripped and fell through a skylight, a distance of 39 feet into a rice storage area of the warehouse below. The employee landed on a 2,000-lb bale of rice, tumbled and fell onto another bale, before landing on the polished concrete floor. The employee sustained contusions and bruising across the upper torso, and complained of sore ribs. The employee had no broken bones or other serious injuries. The fire department responded to the incident and transported the employee to UC Davis Medical Center, where he was treated but not hospitalized. On August 26, 2020, a DOSH inspector reported on site and opened the investigation with both the general site contractor and delivery subcontractor.