INCIDENT #3 DUE TO CONNECTING BREATHING AIR HOSE TO NITROGEN

 An employee hooked the fresh air line of his supplied-air respirator into a plant’s compressed airlines and began abrasive blasting. The plant operators, unaware that their plant air was being used as breathing air, shut down the fresh air compressor for routine, scheduled maintenance and pumped nitrogen into the system to maintain pressure and control the valves in the refinery. The employee was overcome by the nitrogen in the airlines and died of nitrogen asphyxia.

Source:Osha.gov