Abstract: At 3:15 p.m. on May 29, 2017, an employee was kneeling under the arm and quick release attachment of a wheel loader (Caterpillar 966 G series 2). The employee was drilling and cleaning the grease port on the arm of the loader. The pin from the arm of the loader was moved to the side and pulled 1/2 way out of position to expose the grease port in the rear so the port could be cleaned without damaging the pin. The loader arm therefore was resting on a small portion of the pin. Rigging and overhead crane supporting the arm and quick release attachment did not properly hold the part in place when the pin came out. The quick release attachment fell forward and struck employee in the head and back. The employee sustained a fractured vertebrae L1 and a laceration to the head.