Oil and gas extraction requires frequent use of heavy tools and equipment, work in remote and rugged environmental conditions and is physically demanding. These factors may influence the industry's fatality rate, which is seven times higher than for all U.S. industries (according to U.S. Bureau of Labor Statistics. . "Census of Fatal Occupational Injuries"). The authors' previously found a significant relationship between the average annual number of rotary rigs and the industry's fatality rate. This relationship may be a result of more inexperienced workers, longer work hours, and the use of older rigs during times of high demand. In order to identify the most common causes of fatality and the groups of workers most at risk, the National Institute for Occupational Safety and Health (NIOSH) conducted an analysis of fatalities in the oil and gas extraction industry.