Abstract: At approximately 2:15 p.m. on June 9, 2001, Employee #1 was standing on top of a parked oil tanker when he slipped on the oil and fell approximately 10 ft. Employee #1 was not scheduled to work that day. Employee #1 had loaded liquid asphalt into the oil tank a day before the accident and wanted to clean up the mess left on the tank. Employee #1 came in on his own time to do something he was not instructed to do. Employee #1 was hired as a driver for the company, and cleaning the tank is not part of his job. The only person who is allowed to clean the tank would be the owner of the company if necessary, since all the cleaning work is sent outside to other contractors according to the owner. The owner saw Employee #1 came in on his own time and asked him not to clean the tank. Employee #1 told the owner he wanted to at least clean the sides and the owner asked him to do it on the street so that there would not be a mess inside the yard. The top of the tank where the employee was standing could not be guarded. Employee #1 sustained multiple injuries from a 10-ft fall, including a concussion, laceration, and fractures as a result of the accident. Employee #1 was hospitalized.