16.4.5 Hazards of Specific Gases

• Inert Gases - These can cause asphyxiation by displacing the air necessary for the support of life.
  • Examples:  Helium, Argon, Nitrogen
• Cryogens are capable of causing freezing burns, frostbite, and destruction of tissue.
• Cryogenic Liquids - Cryogenic liquids are extremely cold and their vapors can rapidly freeze human tissue.
  • Boiling and splashing will occur when the cryogen contacts warm objects.
  • Can cause common materials such as plastic and rubber to become brittle and fracture under stress.
  • Liquid to gas expansion ratio: one volume of liquid nitrogen will vaporize and expand to about 700 times that volume, as a gas, and thus can build up tremendous pressures in a closed system. Therefore, dispensing areas need to be well ventilated. Avoid storing cryogenics in cold rooms, environmental chambers, and other areas with poor ventilation. If necessary, install an oxygen monitor/oxygen deficiency alarm and/or toxic gas monitor before working with these materials in confined areas.
• Oxidizers- Oxidizers vigorously accelerate combustion; therefore keep away from all flammable and organic materials. Greasy and oily materials should never be stored around oxygen. Oil or grease should never be applied to fittings or connectors.
  • Examples: Oxygen, Chlorine
• Flammable Gases - Flammable gases are easily ignited by heat, sparks, or flames, and may form explosive mixtures with air. Vapors from liquefied gas often are heavier than air, and may spread along the ground and travel to a source of ignition and result in a flashback fire.
  • Examples: Methane, Propane, Hydrogen, Acetylene, flammable gas mixtures.
  • Flammable gases present serious fire and explosion hazards. 
  • Do not store near open flames or other sources of ignition. 
  • Cylinders containing Acetylene should never be stored on their side.
• Corrosive Gases- Corrosive gases readily attack the skin, mucous membranes, and eyes. Some corrosive gases are also toxic.
  • Examples: Chlorine, Hydrogen Chloride, Ammonia 
  • There can be an accelerated corrosion of materials in the presence of moisture. 
  • Due to the corrosive nature of the gases, corrosive cylinders should only be kept on hand for 6 months (up to one year maximum). Only order the smallest size needed for your experiments
• Poison Gases- Poison gases are extremely toxic and present a serious hazard to laboratory staff.
  • Examples: Arsine, Phosphine, Phosgene
  • Poisonous gases require special ventilation systems and equipment and must only be used by properly trained experts. There are also special building code regulations that must be followed with regard to quantities kept on hand and storage.
  • The purchase and use of poisonous gases require prior approval from EHS. Contact the Chemical Hygiene Officer at 607-255-8200.