Deaths involving air-line respirators connected to inert gas sources

During 1984 to 1988, the U.S. Occupational Safety and Health Administration (OSHA) investigated 10 incidents, with 11 fatalities, involving the inadvertent connection of air-line respirators to inert gas supplies. Seven deaths resulted from connecting an air-line respirator supply hose to a line which normally carried inert gas. Four deaths were caused by leakage or backfill of inert gas into a line which normally carried breathable air. Ten of the deaths were from nitrogen and one from argon. The circumstances of the 11 deaths indicated that coupling compatibility and supervisory oversight were major factors in the inappropriate supply of irrespirable gas to the respirators worn by these workers. Conscientiousness among safety personnel to the hazards of asphyxiation by inert gas, and compliance with current OSHA regulations, the ANSI Z88.2 standard, and NIOSH respirator certification approval regulations would have prevented these fatalities.