Abstract: At 2:25 p.m. on October 8, 2020, an employee was servicing a large hydraulic piston. The piston was drained of hydraulic oil. Compressed air was injected to extend the piston. When the piston was extended, two coworkers used a large wrench in an attempt to loosen the cylinder gland. The employee noticed the two coworkers struggling to rotate the wrench at the cylinder gland. The employee thought the piston angle or sagging piston was preventing the wrench from rotating. The employee walked over from his workstation and manually tried to lift the piston and therefore straighten the piston enough to allow the wrench to rotate. As the wrench began to rotate, it released stored energy, causing the wrench to shoot across the room and strike the employee. The employee suffered a laceration to the face just superior to the left eye, soft tissue edema, a fracture to the left orbit, hematoma to the occipital head, and a laceration to the right posterior upper arm. The employee was hospitalized.