Employee had cut a 2 15/16 shaft 36 1/2 long and was placing it in the 4th rack approx. 49"" from the floor on top of two other pieces of pipe when the employee set the shaft down the two pieces of pipe separated allowing the 36 1/2 long shaft to fall through and strike the employee's left foot. The employee's left foot had an impact tear on the outside bottom of the foot.