Abstract: At 7:00 a.m. on November 8, 2019, an employee was working on top of 8-foot A-frame ladder at around 4 feet up. He was wearing steel-toe-work boots, gloves, safety glasses, hardhat and a respirator provided by Unlimited Environmental. The employee was also wearing a pouch for tools and had other tools in the ladder's tray. The crew previously disconnected the branch ducts from the main duct, and each employee was working in a different section of the duct in the same room. The employee cut the strap that held the branch duct from the ceiling on one side, then he repositioned the ladder and cut the strap on the opposite side. The ladder was right below the branch duct between the center and its end; he started descending the ladder slowly, holding the duct with one hand and the ladder with the other hand. The injury occurred when the branch duct started bending and suddenly detached completely from one end hitting the ladder. This motion made the employee lose balance and fall from the ladder 4 feet down. The ladder did not fall, and the branch duct landed away from the employee. The employee suffered an open fracture of the right ankle. He underwent surgery the same day and was released from the hospital two days later.