Abstract: Employee #1 entered a bell jar to clean it wearing a Survivair Mark 2 airline respirator. The employer had decided to stop using removable, cleanable bell jar liners, and employees routinely wore supplied-air respirators when entering the bell jars to clean them with solvents. Management had anticipated a need for nitrogen gas in the airline piping and prepared a bypass to feed it in. Employee #1 was fed nitrogen gas through the completed bypass and died of asphyxia. No knowledgeable supervisor was available on site, and coworkers at the scene had not been trained in first aid or informed about the hazards of nitrogen gas. Key lock systems available at the bell jars were not used to bar entry.