Sleepiness as a result of untreated disorders or sleep deprivation has been identified as a cause of a growing number of on-the-job accidents. At least 25 million Americans have non-traditional work schedules that conflict with their biological clocks. The National Institute for Occupational Safety and Health (NIOSH) reports that tired workers are more prone to accidents both on and off the job because they have difficulty concentrating. In a 1997 publication, Plain Language About Shiftwork, NIOSH outlined some practical tips designed to prevent injuries due to shift work fatigue. NSF has more information in its online publication, "Sleep Strategies for Shift Workers".

http://www.sleepfoundation.org
http://www.cdc.gov/niosh/pdfs/97-145.pdf