University Safety and Assurances

Compressed Gas Cylinder Disposal

Compressed Gas Cylinders


Containers of compressed gas go by many names, including gas cylinders, lecture bottles and high pressure tanks. The containers of gas, even when empty, are likely to contain a residual of at least one atmosphere of the gas. Poison, flammable and corrosive gases must be properly handled to prevent injury to others or to the environment.

Departments are encouraged to rent rather than purchase gas cylinders. When the cylinder is empty, or the need for the gas is over, the gas supplier will pick up the cylinder for refilling and reuse. Cylinders which are purchased may or may not be returned to the manufacturer, while rented cylinders can be returned.

Small amounts of gas can be purchased in smaller rental cylinders rather than purchasing lecture bottles, which are difficult to dispose. Disposable cylinders are a misnomer. UWM may still need to pay for disposal. Acetylene tank in metals shops

Safe Use and Guidelines

Please follow the safe handling precautions outlined in the Gas Cylinder Safety page.

Please take every effort to maintain the labels and identity of compressed gas cylinders. Outrageous costs are required for disposal of cylinders with unknown contents or unknown origins (i.e., manufacturers).

Return all rented cylinders promptly after their use is over.

Please contact Environmental Protection staff for instructions on disposal of other gas cylinders.

Poison Gases

Poison gases (such as Nitric Oxide or Phosgene) represent a significant hazard. Special precautions not otherwise necessary become prudent when using poison gases:
  • Certain poison gases (e.g., Arsine, Phosphine, Ethylene Oxide) can only be used if specific OSHA regulations and safety practices are followed.
  • Emergency procedures should be made clear to all involved, including personnel from adjacent labs and building managers.
  • Poison gas use after normal working hours require the approval of the Chemical Hygiene Officer for your department.
  • Fume hoods and other ventilation need to be tested before use and checked frequently during the project involving poison gas.
  • Notify the staff in Environmental Protection before your first use of the poison gas.
  • The University Police should also be informed about the locations and types of poison gas in use.
  • Document these procedures in your lab's chemical hygiene plan. As with all chemicals, obtain and review the Safety Data Sheet (SDS) for the poison gas. Maintain an extra copy of the SDS in your department's chemical hygiene plan.
Disposal of poison gas cylinders can often cause problems. If the cylinder can not be returned to the manufacturer, UWM can face large disposal costs ($1,000 per cylinder, or more). Even cylinders that can be returned must be shipped on a vehicle which can not simultaneously carry any other hazardous materials or foodstuffs.

Atmospheric or Inert Gases

While atmospheric gases (e.g., nitrogen, argon, etc.) are generally not considered toxic (exceptions: see UWM Diving Safety Manual), these inert gases can still cause dangerous situations to occur if not handled properly. Asphyxiation can occur if too much inert gas displaces the oxygen in the air. Inert gas cylinders still have all the physical hazards associated with other gas cylinders such as high pressure.

Contact staff in UWM's Environmental Protection Program for cylinder disposal as soon as they are no longer needed.

Oxygen and Oxidizers

Oxygen and other oxidizing gases pose additional hazards over usual compressed gas hazards. These gases can enrich an atmosphere so that combustible materials readily ignite or the combustion is accelerated. For example, clothing, paper, and cardboard are very combustible in oxygen enriched atmospheres. Likewise, never use oil, grease or other petroleum products on or near oxidizing gas cylinders. Lecture bottles for disposal

Lecture Cylinders

Lecture bottles are very small compressed gas cylinders, typically 2-3 inches in diameter and 12-18 inches in height. While most gas suppliers offer lecture bottles for purchase, many will not accept the empty or partially full cylinders back for disposal. Lecture bottle disposal can be very costly, depending on the original contents.

UWM researchers should only purchase lecture bottles that can be returned to the distributor. Most distributors, including the most commonly used sources at UWM, do offer a returnable cylinder, although in some cases, these cylinders are slightly larger than typical lecture bottles. Also, keep in mind that distributors’ policies toward lecture bottles are subject to change. In order to avoid costly disposal fees and potential hazards involved in emptying and cutting the cylinder, it is worthwhile to purchase a returnable cylinder, even if it is a bit more than what you need.

If you have unneeded lecture bottles, first call the manufacturer or distributor and ask that they pick up the cylinder for return. If they will not take the cylinder back, Environmental Protection can help coordinate the disposal with one of our vendors. The disposal fee will be charged back to your department.  Also, please indicate whether the cylinder is empty or still contains product above 1 atmosphere of pressure.