Compressed Gases, Cryogens

Gases under pressure are gases that are contained in a receptacle at a pressure not less than 280 Pa at 20°C, or as a refrigerated liquid. This includes gases or gaseous mixtures that can experience a sudden release of pressure or freezing compounds which may lead to serious damage to people, property, or the environment independent of other hazards the gases may pose.


Cylinders cannot be purchased with P-Cards. Cylinders purchased with P-Cards may be subject to immediate return to the supplier, or disposal. Cylinders can be purchased through University StoresSmall quantity liquid nitrogen cylinders are available at Biochemistry Stores.

Toxic gases

Toxic gases (NFPA H=3 or 4) like chlorine, carbon monoxide, phosgene or ammonia can pose serious potential hazards to personnel and therefore special storage and handling measures are required. EHS must preapprove the purchase of toxic gases.

Toxic Gas Cylinder Preapproval List (XLSX)

Handling and Storage

Compressed gas containers must be handled with care and should be stored taking into account the property of the gases contained. Employees should know the hazards of the gases they work with. This information can be found in the SDS of the material. Flammable gases (i.e. propane, hydrogen) must be stored in areas away from sources from ignition and kept separate from oxidizing gases (i.e. oxygen). Use an appropriate regulator, flame arrestor and excess flow valve when using flammable gases.

Toxic gases

Toxic gases will also require a Standard Operating Procedure (DOCX). Toxic gases must be used inside a fume hood or ventilated gas cabinet.

Related policy: Transporting Cryogenic Liquids

Empty Cylinders

Instructions on returning empty cylinders (PDF) are available from University Stores.

Required Training

Training is required for any personnel handling compressed gases or cryogens. This training covers physical and health hazards, proper use, storage, handling, and transport.

  • Compressed Gas Cylinder - required for workers handling compressed gases. Register for the Compressed Gas Cylinder Safety track in Ability LMS.
  • Cryogen Safety - required for workers handling cryogen cylinders. Register for the Cryogen Safety track in Ability LMS.