G‑1   Storage of Chemicals                                                      

                   G‑2   Transportation                                                       

                   G‑3   Disposal of Chemicals, Glass                                 



Small quantities of ordinary chemicals in tightly stoppered, properly labelled bottles may be kept on the laboratory bench; the same is true of solvents in amounts not exceeding about 500 mL. Larger amounts of solvents and all dangerous chemicals in any amount should be stored in ventilated storage cupboards. Acids and bases should be stored separately and strong oxidizers should be kept separate from organics.  All containers should be properly sealed and labelled. The amount of chemicals in a working area should be kept to a minimum.  Do not store chemicals in the fumehood where the vessels might get broken by accident or add fuel to a fire in the event of an explosion or fire. Gas cylinders must be stored and used in an upright position and must be restrained by a chain or clamp to prevent upset. Cylinders should be closed at the main valve and capped when not in use. Cylinders containing toxic gases should be stored in a well-ventilated place. Promptly return empty gas cylinders to the staff person receiving waste in ABB B132, especially those containing toxic gases. In addition to these safety aspects, some companies levy a monthly charge for their gas cylinders; it is worth it economically not to pay to store empty gas cylinders in your lab. Refrigerators should be used primarily to store thermally sensitive compounds.  Even explosion proof refrigerators are not recommended for volatile and toxic substances.


In general, store chemicals only in amounts for which there is foreseeable need. Carefully dispose of the contents of any unlabelled bottles you find in your own storage or working areas.  Be wary of "old chemicals" that may have deteriorated, decomposed, oxidized, hydrated, formed explosive peroxides, etc.; if you have no foreseeable use for them, dispose of them using the proper procedures.



Solvents, acids (in quantities exceeding 500 mL) and all dangerous chemicals must be carried in approved safety carriers.


Gas cylinders weighing more than a few pounds should be transported with a hand truck, with protective caps in place on the cylinder. Be very careful not to drop cylinders or permit them to strike each other violently.  If hazardous materials are to be shipped, know the labelling requirements of the Transportation of Dangerous Goods Act.



The responsibility for the collection, proper labelling and disposal of chemicals and other waste rests squarely on the shoulders of each research worker. Small quantities of most chemicals can normally be disposed of without special precautions in the proper waste disposal containers unless there is a chance that they may cause a reaction in the waste container (see also Table 3).   Each laboratory contains a copy of "Hazardous Chemicals: Information and Disposal Guide". It should be consulted for the most appropriate way to dispose of large and small quantities of many common chemical substances.  There must be NO disposal of chemical or biological waste in the regular garbage.  Local regulations prevent the sink disposal of any of the following categories of material:


            pathogenic tissue specimens                  flammable liquids

            solutions of pH <5.5 or >9.5                 halogenated organics

            heavy metals                                         materials immiscible with water


In general, only very small quantities of mineral acids or alkalis (in solution) can be flushed down the drain after dilution with copious amounts of water (pH >5.5 or <9.5).  Solids (and their solutions) should not be put down the drains.


Mercury should never be allowed to run down a drain, as it will settle in traps where it may not only obstruct liquid flow but also amalgamate with the drain‑pipe metal.  This may have serious consequences for a plumber who might later heat the pipe with a blow torch.


Cyanides must never be flushed down a drain because of the danger of contact with acids flushed down somewhere else and the consequent evolution of HCN.  The hazard is particularly great when several sink drains lead to a common trap.


Label Waste Bottles

For larger quantities of materials and those exceptions listed above, the chemicals should be collected. Each bottle containing waste MUST BE PROPERLY LABELLED at the time it is set out for use. McMaster disposal labels are available from the ABB Science Stores.  The properly filled out labels must be applied to the container before use.  Unlabelled waste will not be accepted for disposal.


Solvents must be separated into two classes: (1) flammable solvents (ether, acetone, methanol, hexane, DMF, THF, etc.) and (2) halogen‑containing solvents (methylene chloride, chloroform, carbon tetrachloride, etc.). Pump oil and old heating bath oil should be collected separately.  Additionally, solid waste (contaminated plastic syringes, disposable gloves, etc.) may be collected.  Any unusual wastes should be labelled with a description of the contents so that the waste can be sorted later according to its chemical compatibilities with other substances.  It is important that such information be provided. Labels for waste bottles may be obtained from stores.


Waste bottles must not be allowed to accumulate in the laboratory.   

Waste should not be allowed to accumulate in the labs.  Please follow this link to download the new procedures for disposing of hazardous waste and the on-line submission form: http://www.workingatmcmaster.ca/eohss/labs/hazardous-waste/


Glass Disposal


Glass waste includes glassware pipettes, emptied glass vials, used test tubes, etc. No glass refuse is to be placed in regular waste bins in the lab.  Cleaning staff still suffer injuries from pipettes thoughtlessly placed in ordinary garbage.  All waste glass must be cleaned before disposal.


Larger empty bottles may be left in the hallway outside labs for pick up by maintenance staff.  These bottles must be cleaned of all residues (let solvents evaporate in the fume hood) and the labels defaced with an X mark.


"Star Cracks"                        Any round bottom flasks with "star cracks" must be discarded in the broken glass waste.

Broken Thermometers          Broken thermometers containing mercury must not be placed in broken glass waste but should be treated as chemical waste.