Abstract: On February 19, 1999, six employees were replacing 2-in. by 2-in. by 7-ft stakes used to support grapevines in a vineyard. The vines were separated by 8 ft in the same row and the rows were 12 ft apart. The employees used two hydraulic stake drivers attached to an ASV Posi-track tractor (Model 4520). The stake drivers were positioned 12 ft apart so the employees could work on two rows of vines at one time. The tractor operator drove between rows and positioned the tractor so that the stake drivers were over the stakes. One employee's task was to hold the vine back, so another employee could position the stake. After the stakes were positioned, the stake driver operators pulled the control levers that caused the stake drivers to descend and force the stakes approximately 14 in. into the ground; and then the crew moved to the next location, 8 ft ahead. As Employee #1 walked along side the tractor, his foot was caught on the track, causing him to fall. He sustained a fractured leg and was hospitalized.