required to perform testing in all confined spaces that have contained a flammable, combustible or toxic substance. Certification in civilian settings can be performed by any employee who is trained and authorized by the employer. The Entry Supervisor, under OSHA regulations, is designated by the employer and ensures that the space is safe to enter and all hazards are controlled. Guidance provided by OSHA stresses the importance of establishing procedures focused on preventing unauthorised access. It states that temporary confined space barriers need to be fitted "promptly" once entrance covers are removed for access. This prevents unauthorised access, accidental falls into the space and foreign objects entering in. In the United States, agricultural operations are exempted from regulations governing permit-required confined spaces (which is specific to general industry), but they are still required to identify and control confined space hazards. Injuries and fatalities Injuries and fatalities involving confined spaces are frequent and often involve successive fatalities when would-be rescuers succumb to the same problem as the initial victim. In the 1980s, approximately 60% of fatalities involve would-be rescuers and more than 30% of fatalities occur in a space that has been tested and found to be safe to enter. One example was in 2006 at the decommissioned Sullivan Mine in British Columbia, Canada when one initial victim and then three rescuers all died. Accidents in confined spaces present unique challenges and are often catastrophic, such as the Xcel Energy Cabin Creek Fire in 2007. 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 of Occupational Safety Health (NIOSH) and the Mines Safety and Health Administration (MHSA) with a breakdown of their causes. Researchers believe that the following numbers are only a fraction of the fatal confined space accidents that actually occurred as many locations are not initially identified as confined spaces, OSHA reports did not include non-hazardous confined space fatalities in their studies prior to 1982, NIOSH still do not include non-hazardous confined space fatalities in their studies and many American states do not note the presence of confined spaces in fatality reports submitted to OSHA. Fire and Explosion (OSHA 1982a): 50 confined space incidents from 1974 to 1979 with 76 fatalities.The majority of incidents were caused by worker error or faulty equipment. Lockout-tagout (OSHA 1982b): 83 confined space incidents from 1974 to 1980