Abstract: At approximately 4:15 p.m. on December 15, 2001, an employee was placing a wooden block under the boom of a 255B Madill yarder when it fell on him. The yarder was loaded on a lowboy to be transported to the next job site. While lowering the boom tower, the employee decided to place a 64 by 8 by 6 inch block underneath the boom. As the operator continued to lower the boom the guylines could not hold the weight and it fell down striking the employee. He was transported to Good Samaritan Hospital where he was hospitalized and treated for his injuries. He suffered six broken vertebrae and a severed spinal cord.