Disposal Procedures

Disposal of Waste Chemicals

Information regarding Duke University's Chemical Waste Policy is available from the OESO.  Subjects covered below are specifically applicable to disposal of waste chemicals in the Department of Chemistry.

Hazard Categories

Chemicals of different hazard groups require different disposal methods. Therefore every effort must be made by the researcher to help identify the hazards associated with a chemical prior to disposal. Hazard categories of interest are as follows:

  1. Flammables / Ignitables

    Any liquid, solid, or gaseous material with a flash point less than 60 °C (140 °F) or, when ignited, burns so vigorously that it creates a hazard. Also included under this heading are any strong oxidizing materials, organic solvents (ether, xylene, toluene, etc.), alcohols (methanol, ethanol, butanol, etc.), paint thinners, and many cleaning compounds. Oxidizers, such as hydrogen peroxide and benzoyl peroxide, may cause a material to ignite spontaneously and are therefore included in this class.

  2. Corrosives

    Any aqueous solution with a pH less than 2.5 or greater than 12.5 is a corrosive hazardous waste. Strong acids (hydrochloric acid, sulfuric acid, etc.), strong bases (sodium hydroxide, potassium hydroxide, etc.), and any other materials which will cause steel to rust significantly are also considered to be in this group.

  3. Toxics

    Most pesticides and any of the 750 additional compounds named in 40 CFR 261.33 (listed in the Duke University Chemical Waste Policy) are considered to be toxic. Among the compounds named in 40 CFR 261.33 are the known carcinogens, mutagens, and teratogens. Potassium dichromate, pesticides (enrin, lindane, etc.), and silver nitrate are some examples of this group.

  4. Reactives

    Any material which is unstable, reacts violently with water, forms explosive mixtures with water, is a cyanide or sulfide bearing waste, or is capable of detonation either deliberately or inadvertently, such as sodium metal, potassium metal, dry picric acid, sodium azide, or peracetic acid, is a reactive hazardous waste. Do not place explosive chemicals into a package for pickup until receiving instructions from the OESO. If you have any questions concerning your waste category, contact Ms. Kathleen Ingram at the OESO, 684-2794.

  5. Metals

    Separate Waste containing arsenic, barium, cadmium, chromium, lead, mercury, selenium or silver. List the amount or % of each metal present in the waste container.

  6. Radioisotopes

    Separate radioisotope waste. List the specific isotope(s), the amount of each isotope and the medium the isotope is in.

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Hazardous Waste Disposal

In order to dispose of chemical or radioactive waste your lab must be registered with the Environmental Programs Division of the OESO. Upon registration your lab is issued a generator ID and barcode labels which you will need for waste disposal procedures. If you do not know the generator ID for your lab contact the OESO directly. Contact the OESO (684-2794) if you need additional barcode labels for your laboratory. Information on all types of waste is maintained on the OESO website under the "Environmental Programs" section. The OESO maintains a list of chemicals that are considered to be hazardous (called the P waste list), policy and procedure , and a waste log. Be sure to follow procedures outlined by the policies. The OESO expects each lab to put forth their best effort in minimizing waste generation in the lab. To assist in the effort the OESO operates a chemical exchange program to provide, free of charge, unused chemicals to laboratories at Duke. The inventory for the exchange is created from unopened chemicals received as waste from the University and Medical Center. Call the OESO for more information about inventory and procedures for obtaining chemicals from the exchange.

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Halogenated and Non-Halogenated Waste Solvents

Whenever possible, halogenated and non-halogenated solvents should be placed in separate containers for waste disposal. This is because the disposal cost for halogenated materials is significantly higher than that for non-halogenated materials. Flame resistant, five gallon, red cans can be obtained from the OESO for this purpose. These cans are to be used only for solvents and should never be used for disposing of any heavy metals, reactives, acids, bases or bromine. Cans are marked with either yellow (for non-halogenated solvents) or green (for halogenated solvents) tape. In addition, each can has an associated (yellow or green) inventory sheet with a place for a single barcode label and room to indicate the volume and name of each waste solvent added to the can. Each laboratory can have a maximum of four red cans for disposal of solvents. Solvent cans are picked up by OESO personnel. To let the OESO know that your solvent cans are full, complete a disposal request through the Waste Pickup Request System. Cans must be barcoded and paperwork filled out to the best of your ability, otherwise your solvent can will not be picked up. Due to federal and state regulations governing disposal, it is vitally important that the contents of each red can are accurately reflected on the paperwork. Links to logsheets, waste accumulation labels, small container labels, the waste pickup request sytem, etc are located on the OESO website: Environmental Programs Division, Chemical Waste Section.

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Request for Pickup of Other Chemical Waste

To dispose of chemical waste not collected in the red cans, each item will need to be barcoded, inventoried and submitted for waste disposal through the Waste Pickup Request System. You will need to list the proper name of the chemical (abbreviations and chemical structures are not acceptable) and the size of the container on the pickup request form. Once your request is received the OESO will process the request and pickup your waste. In the event that your request is not properly completed, or there are chemicals on the request form which are not already in the OESO database, pickup will be delayed. Under normal conditions your waste should be picked up within 5-10 days after its submission. Once you have submitted a request for pickup, keep the waste in an easily identified area and let at least one other lab member know that you are expecting a pickup and the location of the waste materials. Be sure, also, that the waste is not in a leaking, or improperly sealed container. If there are any problems with the condition or containment of the material you will have to resolve them before pickup is completed.

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Special Notes

Waste containing arsenic, barium, cadmium, chromium, lead, mercury, selenium or silver are particularly difficult and expensive to dispose of. Consequently, specific information giving the amounts and types of metals present the in the chemical waste must be included on the chemical pickup request form. If the information is not provided on the form, the OESO will contact your lab prior to pickup to obtain the missing information. If the exact amount of a metal in the waste is not known a good estimate should be made based on how much material was used in the experiment generating the waste. Mercuric cyanide does not currently have a disposal route in the United States. Labs are strongly encouraged to find a substitute for this chemical. In the event that your lab must use mercuric cyanide, please get approval from the OESO prior to purchasing the material.


Disposal of Empty Disposable Gas Cylinders

The contents of lecture bottles must be identified prior to disposal with the OESO. Every effort should be made to recycle a used, but not empty, lecture bottle by giving it to another researcher when your lab no longer needs the material.

  1. Open valve fully so that the top of the container may be completely unscrewed or sawed off prior to burial in a landfill. Then tag the cylinder for waste pickup.
  2. If the tank has an automatic valve that cannot be left open, (e.g., disposable propane tanks for torches) simply tag it for pickup when empty.
  3. Do not vent toxic or other unsafe gasses in the fume hood. Instead, you should attempt to cycle the bottle to another researcher, or if it clearly needs to be emptied, you should trap the gas in an appropriate solution for disposal.

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Disposal of Used Silica Gel

Used silica may be left in a hood, to evaporate solvent, packaged in thick plastic bags or sealed drums and disposed of in the dumpster at the loading dock provided that it does not contain other hazardous chemicals. If it does contain hazardous chemicals dispose following guidelines for chemical waste. Do not dispose of silica gel in trash cans or leave it for housekeeping to remove.


Disposal of Rinse Solvents

When you rinse glassware with a solvent, such as acetone, collect the rinse solvent in an appropriate container. Preferably, rinse your glassware over a funnel that empties into a container such as a bottle or used acetone can. The container should then be tagged for waste pickup using normal procedures. Our general policy is that nothing except water should go down the drain.

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Disposal of Empty Bottles and Cans

Housekeeping will collect empty bottles and cans left in the main hallway. To avoid exposing housekeeping staff to chemicals, any bottles or cans that you place in the hallway for disposal must be thoroughly cleaned and rinsed.  


Disposal of Broken Glass

Place all broken glass items in the cardboard containers designated for the disposal of broken glass. The box should be properly labeled, and taped shut when it is full.  Housekeeping will dispose of properly labeled and taped broken glassware boxes. 

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Disposal of Hypodermic Syringes and Needles

Used needles cannot be placed intact in regular waste receptacles since they may injure persons who must handle our trash. Use only containers specifically designated for disposal of syringes and needles. These containers are available upon request from OESO. Full containers of used syringes and needles should be tagged as chemical waste as described above.


Disposal of Used Pump Oil

Used pump oil should be tagged as chemical waste as described above.

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Disposal of Smelly Trash

In order to avoid exposing Housekeeping staff to unusually odoriferous trash, bag and tie the trash before putting it in waste baskets.   


Disposal of Chemicals in the Trash is Forbidden

If the housekeeping staff sees (or smells) chemicals in the trash, they will not pick it up. The Administrative Coordinator will be notified, and the lab occupants will be contacted to correct the problem.

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