An employee and a co-worker were conducting work on the pipeline right-of-way. The co-worker went across the bridge to help guide the employee as he drove a side-by-side utility task vehicle (UTV) across the bridge. As he crossed the bridge, the boards along the right side began to give way. The employee hit the accelerator, trying to make it across the bridge. He made it across and the UTV veered to the right, ultimately striking a tree. The UTV rode up the side of the tree, coming to a stop while leaning against the tree, and the employee fell out of the vehicle. The employee suffered a broken rib on his left side, a broken sternum, and fractured vertebrae.