An employee was in the trailer inspection lane at a facility to have his trailer inspected for suitability to load. There was a small amount of debris inside the trailer. He climbed into the trailer, collected the debris, and put it at the rear of the trailer for disposal. He then climbed down from the trailer and stepped onto the ground. The pavement was wet and sloped toward a drain, causing him to lose his balance and fall to the ground. He attempted to catch himself with his left hand and arm, and his left wrist was fractured as a result of the fall. He was hospitalized and had surgery.