A tank was taken out of service for repair. The scope of work included replenishing the integrity of the tank’s stairs; i.e. the steps and their vertical supports. The method employed was to work from the ground to the top, removing every second step and the vertical supports so access to the tank could be maintained while the stairs were repaired. However, because of the state of the supports, the job method had to be modified and two steps in succession were removed. The hazard was recognized and the area clearly identified by way of hazard tape. Workers passed up and down safely several times past the gap in the steps. However, on the way down at the end of the second day, an employee stepped into the gap and fell to the ground. He was taken to hospital, but died a short time after arrival.