The University of Arizona


Risk Management and Safety

Chemical Safety Bulletins


Incident: Toxic Gas Inhalation


What happened? (1993) A Materials Handler was preparing a lecture bottle of arsine (PDF format) gas (AsH3) for shipment back to the manufacturer. The lecture bottle still had the flow control valve in place and needed to be removed before shipment. Upon tightening the cylinder valve and loosening the control valve fitting, the Materials Handler heard the leaking of gas and detected an indescribable odor. He quickly tightened the control valve fitting to stop the leaking (apparently the cylinder valve would not seal correctly).


The Material Handler immediately called for medical advice and was taken to the University Medical Center emergency room for a medical evaluation. Fortunately no immediate or delayed acute affects from the exposure were observed.


Why did it happen?

  1. The users of the compressed gas did not properly prepare the compressed gas cylinder for shipment.
  2. A compressed gas cylinder was taken from the laboratory for disposal without the cylinder being properly prepared for shipment.
  3. A compressed gas was handled without the handler having a thorough knowledge of the hazards and without taking adequate precautions.

How can a similar occurrence be avoided?

  1. When compressed gas cylinders are empty or partially full and no longer needed, the cylinder valve must be closed and the valve outlet plug and the cylinder valve protection cap replaced (if supplied) before requesting cylinder disposal. In addition, if the compressed gas is a known carcinogen, a known reproductive toxin, or a highly toxic gas, it must be appropriately identified with a warning label (PDF format) (e.g. CANCER AGENT, REPRODUCTIVE TOXIN, HIGHLY TOXIC SUBSTANCE).
  2. Compressed gases which are not prepared in the aforementioned manner will not be picked-up for disposal.
  3. No one should use or handle a compressed gas (or any other hazardous chemical) without knowing the physical and health hazards of the gas and the safety rules and procedures that apply (see Chemical Management Best Practices – Distribution).

Arsine is a highly toxic, carcinogenic, and flammable gas and must be handled with extreme caution. Acute exposures can cause rapid or delayed destruction of red blood cells with subsequent kidney failure. Over 200 cases of arsine poisoning have been reported, with over 20% of these resulting in fatalities!


The recommended exposure limit (TLV) to arsine is only 0.005 parts per million (ppm). It is detectable by a mild garlic-type odor at approximately 0.5 ppm and it is immediately dangerous to life and health at concentrations as low as 3 ppm!


Arsine is an extremely hazardous chemical that requires prior approval (Chemical Safety Level 3 or CSL-3) by the Institutional Chemical Safety Committee (ICSC). For approval, the Minimum Requirements for Toxic/Corrosive Gas Use (PDF format) will at least be required by the ICSC.