In 1999, North West OHS released a study of confined space fatalities based on reports from the Occupational Safety and Health Administration (OSHA), National Institute for Occupational Safety and Health (NIOSH), and the Mines Safety and Health Administration (MHSA) with a breakdown of their causes. There are three categories of confined space rescue: self-rescue, nonentry rescue, and entry rescue. A nonentry rescue involves attempting to extricate an incapacitated person without having anyone else enter the confined space. This can be done via a safety line attached to the personnel in the confined space or by grabbing the personnel with a rope, strap, or pole and pulling them to safety. Once the strap is looped around a hand or foot, its attached rope is pulled by rescuers, tightening around the arm or leg and pulling the victim out of the confined space.