What happened? (Spring 1996) A student was conducting an experiment which involved the flow of argon gas. The experimental apparatus was set-up in a small room (6' x 7' x 9') with very little ventilation. The room had an open door. During the experiment, the student recalled argon occasionally blowing in her face from leaks in the apparatus. After about 30-40 minutes of gas flow (this is considerably longer than typically required for this experiment) she began to feel dizzy and her face felt numb. Her vision began to blacken on the edges and her legs could no longer hold her. She had difficulty breathing. While she was trying to turn off the gas and catch her breath, the TA approached and asked how she was. She could not remember responding but remembers being instructed to leave the room. She sat in the hall – unable to stand. She continued to have difficulty breathing. She felt disoriented and the back of her throat felt numb and tingly. A concerned passerby called 911. Paramedics arrived and treated her.
One week prior to this incident the student had conducted the same procedure for a shorter time period and felt dizzy and sick to her stomach. At the time, she thought it was related to her not eating breakfast that day.
Why did it happen? Available oxygen in the room was displaced by argon gas and/or argon flow was directly inhaled. Conditions which promoted this included: minimal room ventilation, small room size, leaking apparatus, and the unusually long experiment time (i.e. a greater amount of gas flowed). Also, the student and the TA were not aware of the potential hazard nor the signs of over exposure and did not recognize what was happening.
Argon is a known as a simple asphyxiant. It is inert and causes no toxicological effects but it can reduce available oxygen for breathing. Symptoms of asphyxiation can include air hunger, fatigue, reduced visual acuity, tunnel vision, dizziness, headache, numbness and tingling of extremities, poor judgment, memory loss, and decreased ability to escape.
How can a similar occurrence be avoided? As with any chemical or procedure you should know the associated hazards and hazard controls in advance (see Chemical Safety Information). Argon and other inert gases should only be used and stored in well ventilated spaces. In this instance, the experiment was moved to a larger, better ventilated space, leaks in the experimental apparatus were fixed, and the potential hazards of the procedure were included in the written protocol and discussed in the lab.
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