March 2004


The Office of Environmental Health and Safety (EH&S) does not routinely collect or manage compressed gas cylinders, including lecture bottles, for hazardous waste disposal. Researchers and other users are instead required to use proper management techniques or purchase cylinders from companies that accept them for return. Larger cylinders purchased from our current cylinder vendor are generally not a problem, however certain specialty gasses purchased as lecture bottles have been. Disposal costs for lecture bottles that cannot be returned can run anywhere from $100 per cylinder for inert gases, to over $1,000 for unusual or highly toxic gases. Your cooperation in following these procedures will be helpful for you in making decisions in purchasing and managing compressed gasses and avoiding costs for disposal being billed to your department.

Check to see if there are any surplus lecture bottles amongst your colleagues within the University. If none are available, then purchase your gas in a returnable and/or refillable lecture bottles or cylinders. Over the last several years, many vendors have developed alternatives to lecture bottles and you should contact your sales representative to learn more about these alternatives. If none of these options are possible, then you will need to plan for the proper management of the lecture bottle when it is empty or no longer needed.

Contact the manufacturer or vendor of the lecture bottle to confirm their policy on returns. Follow the instructions given by the vendor to ship the lecture bottle. They will be able to provide required shipping information. Call EH&S if you need any assistance. The following companies are currently known to take back their lecture bottles: Air Products, Aldrich, American Environmental Instruments, Cambridge Isotope Labs, Farchan Laboratories, Matheson, MG Industries, Morton International, Ozark Mahoning, PCR Research Chemicals, Pfaltz and Bauer, Scott Specialty Gases and Spectra Gases. Each of these companies has special requirements for accepting lecture bottles for return so it will be necessary for you to contact them beforehand.

If you no longer have a use for a partially full lecture bottle you should attempt to find someone within the University that can use it. If the gas is Freon, it may be possible to recycle it with our Physical Plant Department, which can be reached at x4886. If the lecture bottle cannot be reused within the University, then return the lecture bottle to the manufacturer. If the gas is non-hazardous (air, argon, carbon dioxide, helium, krypton, neon, nitrogen or xenon) then you may vent the gas to fume hood. After the lecture bottle is empty you must then remove the valve and the remaining metal carcass can then be recycled or disposed in the regular trash. If the lecture bottle contains a poison or other hazardous gas and none of the above options are workable, then it may require disposal as a hazardous waste.

Removal of valves from lecture bottles can present a significant hazard if the cylinder is not fully discharged or if there are hazardous chemical residues present. Lecture bottles that held flammable gases may still present a fire or explosion hazard, while those that held corrosive, poisonous, or reactive gases may still have sufficient residues to present a hazard to the person working with the cylinder. Remaining residues may require it to be managed as a hazardous waste. In general, all pyrophorics should be excluded from this procedure. Eye protection and gloves should be minimum protection whenever removing valves from lecture bottles.

Ensure the lecture bottle is empty.


  • Visually inspect the valve to see if there are obvious physical defects or corrosion that may have affected the valve. If there is a defect or corrosion problem, do not attempt to manipulate the valve. Rather cap or plug the outlet and dispose of as a hazardous waste.
  • If the valve appears to be safely operable, check the gas pressure within the lecture bottle by attaching the correct Compressed Gas Association pressure regulator. Once the pressure, if any, had been determined, remove the regulator and then place the lecture bottle in a fume hood and carefully open the valve. Allow the lecture bottle to set for a few minutes to assure that the pressure inside it is at the ambient level.


Remove the valve.


  • Assess possible hazards from gaseous residues and select personal protective equipment as appropriate. Lecture bottles that contained a flammable or hazardous gas should be purged with nitrogen three times. Place the lecture bottle in a vise and remove the valve. The lecture bottle can then be sent to a recycler (contact Building Services at x 2757) or disposed of in the regular trash. All labels on the lecture bottle should be defaced.


Any lecture bottle that is not returnable or cannot be managed on site, will require management as a hazardous waste. EH&S will arrange for most cost effective and environmentally sound disposal for you. Lecture bottles will not be accepted and picked up until EH&S receives an appropriate budget number in which to bill back the disposal cost.
All lecture bottles that are hazardous must be clearly identified as “hazardous waste” on the label. In addition, the date when the waste container was declared a waste, the physical hazards of the waste (e.g. corrosive), as well as an identification of the chemicals or chemical mixtures, must all be put on the label. Hazardous waste disposal labels are available through OEHS and should be used when declaring a material a hazardous waste. Please call in advance for labels so they can be sent to you via University mail prior to the scheduled pick-up. In addition to the above labeling requirements, the approximate pressure (psi) must also be noted on the label.

The U.S. Congress has made waste minimization a national policy and goal of each waste generator. You as a user of compressed gasses, have the responsibility to minimize the amount of gas managed as a hazardous waste. Waste minimization has benefits such as decreasing your exposure to hazardous substances, protection of the environment, and the overall reduction in the cost of disposal which frequently can exceed the original cost of the gas by 10 or more times. Waste minimization includes such things as changing procedures, reducing scale and substituting materials. In addition, if you have gases that you no longer have a use for and feel it could be recycled within the University, please contact your colleagues or EH&S. A Chemical Recycling Redistribution List is now available on the Hazardous Waste Management section of the OEHS Web Site, to allow chemicals and gasses to be reused across campus rather than being disposed of as hazardous waste.

If you have any questions or would like to schedule disposal of your compressed gas as a hazardous waste, please contact the office of environmental health and safety at x2769. The OEHS website is