EE was injured when a section of grating failed at the R-52 Bulk Loading Tower. EE dropped his tool underneath the stationary counterweights of the tower. He knelt down in order to crawl to the tool, when the grating failed. He fell approx 18' to the water below the tower, approx 2 1/2'. Suffered a laceration to upper lip, a contusion below his right eye and abrasions to shin.