Chemical waste
Guidance on how to package, label, store and dispose of chemical waste on the St. George campus, including what constitutes chemical waste and special cases.
Chemical waste is not treated on campus; the majority are recycled. Of the organic waste produced, 100% is recycled through various industrial processes. Depending on the composition, 50 to 75% of inorganic chemical waste is also recycled. Those chemicals that cannot be recycled are treated by external contractors.
What is chemical waste?
Chemical waste includes solids, liquids or gases containing or contaminated with any of the following:
- flammable solvents (for example, acetone, alcohols, acetonitrile)
- leachate toxic materials (for example, heavy metals, pesticides)
- corrosives (for example, hydrochloric acid, potassium hydroxide pellets)
- reactives such as oxidizers, cyanides, sulphides, explosives, unstable materials and water-reactive materials (for example, sodium metal, benzoyl peroxide)
- toxic materials, including mutagenic, carcinogenic, acute or chronic toxicity materials (for example, chloroform, ethidium bromide)
- polychlorinated biphenyls (> 50 ppm concentration)
- non-returnable gas cylinders
Packaging chemical waste
In addition to the general packaging requirements outlined in Section 4, these specific requirements for chemical waste must be followed:
Never mix incompatible materials in a single container (see Section 5.2.4.1).
Wastes must be stored in containers compatible with the chemicals stored. For example, hydrofluoric acid waste must not be stored in glass containers, corrosive chemicals must not be stored in metal containers, etc.
Solvent safety cans should be used to collect and temporarily store large volumes (10-20 litres) of flammable organic waste solvents. The researcher is responsible for providing these cans to the laboratory. Cans submitted for disposal will be emptied and returned promptly to the laboratory if identified with the building and laboratory room number. This occurs at Lash Miller Chemical Laboratories only.
Do not insert precipitates, solids or other non-fluid wastes into safety cans.
Package halogenated and non-halogenated solvents separately, if possible. The university pays a premium for disposing of halogenated solvents (for example, chloroform and carbon tetrachloride).
Do not package solid chemical waste into biohazard bags, because this incorrectly indicates a hazard that is not present.
Buildings with central waste storage have drums for contaminated glass and plastic. Lab staff can empty their containers into these drums (see picture below). No chemical liquids or dry chemical powders should be placed in these drums. Caps should be removed from contaminated bottles before being placed in the drums to show they do not contain chemical liquids.
Labeling chemical waste
In addition to the general labelling requirements outlined in Section 4, these specific requirements for chemical waste must be followed:
Attach a chemical waste label directly to the waste container. Chemical waste labels are available free of charge from the Environmental Protection Services team.
All information requested on the chemical waste label should be provided. Chemical generic names of the chemicals must be listed. No abbreviations, acronyms or trademark names are to be used. Vague categories (for example, inorganic waste) are not acceptable. See Figure 1 for a completed example of a chemical waste label. Download the PDF fillable version.
Storing chemical waste
In addition to the general storage requirements outlined in Section 4, these specific requirements for chemical waste must be followed:
Waste chemicals should be stored in the building’s central waste-holding facility. Should such a facility be unavailable, the chemical waste should be temporarily stored in the generator’s laboratory. To find the central chemical waste facility location in your building, please contact the Environmental Protection Services team.
All safety precautions required for handling and storing chemicals will also be observed for the generated wastes.
Waste should be segregated according to compatibility groups such as acids, bases, flammables, oxidizers and water reactives and not according to alphabetical order. See Section 5.2.4.1 for chemical compatibilities or contact the Environmental Protection Services team.
Dispose of aging containers promptly. Some chemicals are time sensitive and may degrade into very hazardous by-products; for example, ethers may degrade to form explosive organic peroxides.
Chemical compatability
When preparing chemical waste for disposal, it is the generator’s responsibility to ensure that incompatible chemicals are not stored in the same container. Waste containers should be stored according to their compatible chemical reactivities. A few general examples are:
Acid-reactive compounds (such as cyanides and sulphides), which liberate gaseous products when acidified, should not be mixed with any inorganic acid (for example, sulphuric or hydrochloric acid).
Organic acids (such as glacial acetic acid) should be segregated from inorganic acids. Generally, inorganic acids are oxidizing agents, while some organic acids may be either reducing agents or combustible.
Water-reactive materials (such as sodium) should be kept away from any water source.
Oxidizers (that is, any inorganic compound that assists fire such as hydrogen peroxide, lead nitrate) should never be mixed with organic materials (for example, organic bases such as pyridine, aniline, amines, flammable solvents such as toluene, acetone) or reducing agents (for example, water-reactive chemicals such as sodium).
Note: Perchloric acid, although an inorganic acid, is a powerful oxidizing agent and should be considered a powerful oxidizer in its concentrated form.
For any wastes that require special handling, such as organic peroxides, PCBs (polychlorinated biphenyls) or explosives, consult the Environmental Protection Services team.
Special cases
The preceding procedure dealt with common teaching and research chemical wastes generated by U of T. Occasionally, chemical wastes are generated that require additional or special handling, as discussed below.
Asbestos
Asbestos-containing materials, such as Bunsen burner pads, gloves, etc., are disposed of by specially trained staff. Contact your building’s property manager.
Batteries
Household batteries should be placed into battery recycling containers placed around campus. Learn more about recycling batteries on campus. Please apply tape to all lithium battery terminals before dropping them off. The Environmental Protection Services team collect all other batteries (12 volt or larger).
Empty drums
The Environmental Protection Services team remove empty drums (20 to 205 litre capacity).
Ethidium Bromide
All materials contaminated with ethidium bromide, including solids such as gloves, should be packaged in a secure container, labelled and treated as chemical waste. Gels contaminated with ethidium bromide should be packaged in leak-proof plastic containers (no garbage bags) and disposed of as chemical waste.
Explosives
Do not handle explosive materials. Examples of explosives include materials such as trinitrated compounds (for example, TNT), dry picric acid (<20% by weight water content), fulminated mercury and heavy metal azides (for example, lead azide). These materials require special handling for disposal. These materials must be checked frequently for signs of deterioration and aging. These signs include ‘sweating’ of a container, bulging, crystal formation around the cap, etc. Deteriorating explosive materials are potentially more dangerous to handle than new explosives. Inform the Environmental Protection Services team immediately.
Gas cylinders
Follow our gas cylinder waste procedures.
Mercury thermometers
Mercury thermometers for disposal should be treated as chemical waste. Broken thermometers should be considered contaminated, and all free liquid mercury should be collected and packaged in a leak-proof container, together with all contaminated solids such as glassware, gloves used during the clean-up, etc.
Paint cans
Expired or spent paint cans are normally disposed of as chemical waste.
Peroxidizable compounds
These materials should be ordered in small quantities (less than six months’ supply) and dated when the container has been opened. Even if a commercial inhibitor has been added by the manufacturer, organic peroxide formation can begin within six months following exposure to air. Ordering smaller quantities and reducing the volume of these materials in storage encourages the quick turnover of inventory and reduces the likelihood of peroxide formation. Organic peroxides are explosive.
The following materials are potential organic peroxide formers:
- acetal
- decahydronapthalene
- dicyclopentadiene
- diethylene glycol
- dioxane
- ether isopropyl ether
Polychlorinated biphenyls (PCBs)
Chemical waste collection schedule
To request chemical waste collection, please email eps.hazdisposal@utoronto.ca or call 416-946-3473.