EE had just finished fueling his Komatsu PC400 and was climbing down to set his fuel nozzle in the track and lost balance and fell approx. 4' to a steel deck of the barge. He landed on the left side of his head and shoulder. Gateway Dredging employees observed a 3"" laceration and EE said he had pain in his left shoulder, rib and back area. Immediate decision was made to call 911.