On 26 Sep.14 at 14:50 hrs., crane operator was offloading the cargo from MV VOS Ares. While lifting the food container (no.ESS-53 Chiller Food container, located on forward part of starboard side) over deck 1 meter, he lost the control over this operation because his chair suddenly slid forward caused the container moved toward port side of cargo deck and hit the chemical tank and wooden box, resulted in slight dent at top part of chemical tank and minor damaged wooden box in metal basket. The food container has no damage. Note: 1. There is no injury, boat deck crew was able to avoid staying in line of fire and escaped from the vicinity of this container. 2. Wave high 0.5 meter, wind speed 7 knots