Material Safety Data Sheets (MSDS)

Material Safety Data Sheets, or MSDS, contains important information about the controlled product you are using and is one of the three core elements of the WHMIS program at UWaterloo.

The MSDS when used to supplement the information found on WHMIS labels and in conjunction with an effective education plan will give you the knowledge you need to work safely and confidently with any hazardous material.

It is important to remember that an MSDS expires after 3 years. When referencing an MSDS ensure that you check the date of preparation to make sure that the MSDS is still current. If the MSDS is out of date you can request a current copy from the supplier of the controlled product.

MSDS availability

Every WHMIS controlled product in your work/study area must have an associated MSDS readily available.

MSDSs cannot be kept in locked cabinets/rooms/desks, they must be accessible by all UWaterloo personnel that work with or near the controlled product.

An MSDS may be kept in either hard (i.e. paper) or soft (i.e. electronic) format as appropriate, with the following requirements.

When required, hard copies must at all times be:

  1. Visible, and
  2. Accessible

Soft copies must be accessible through a computer to all employees/students in the area where the controlled products are stored or used. Ready access means:

  1. Having a userID and password, if the computer is security enabled
  2. Knowing the server and file path to find the information
  3. If applicable, knowing how to use the MSDS management software, and
  4. Having privileges and knowing how to print a hardcopy.

Whether the MSDS is a hard or soft copy it must not be older than 3 years.

Maintain MSDS as follows:


  • Hard copies must be maintained for:
    • Routinely (weekly or more frequently) used controlled products, and
    • Controlled products that are present on:
      • A pipe
      • A piping system including valves
      • A process vessel or
      • A reaction vessel
  • Soft copies may be maintained for all remained controlled products.

Controlled product storage areas

  • Soft copies are acceptable.
  • Hard copies must be made available when a material is brought out of storage.

Controlled product dispensing areas

  • Hard copies must be maintained for all controlled products dispensed in the area.

Glossary of MSDS terminology



Acute exposure- A short-term exposure, usually occurring at high concentration.

Acute health effect- An effect that develops either immediately or a short term after exposure.

Auto-ignition temperature - The minimum temperature required to initiate or cause self-sustained combustion, in the absence of a spark or flame.


Biohazardous infectious material- A material that contains organisms and the toxins produced by these organisms that have been shown to cause disease or are believed to cause disease in either humans or animals.

Boiling point - The temperature at which a liquid changes from a liquid to a gas, at normal atmospheric pressure.


Carcinogens - Agents/compounds that may induce cancer in humans.

CAS registry number- A number assigned to a material by the Chemical Abstracts Service (CAS) to provide a single unique identifier.

Chemical formula - Sometimes called the molecular formula, indicates the elements that make up a chemical.

Chemical name - A proper scientific name for the active ingredient of a product.

Chronic exposure - A long-term exposure, usually occurring at low concentration.

Chronic health effect- An effect that appears a long time after exposure.

Coefficient of oil/water distribution- The ratio of the solubility of the chemical in an oil to its solubility in water.

Combustible liquid - A liquid which has a flash point above 37.8°C.

Compressed gas - A material which is a gas at normal room temperature (20°C) and pressure but is packaged as a pressurized gas, dissolved gas or gas liquefied by compression or refrigeration.

Condensation - The process of reducing from one form to another denser form such as steam to water.

Controlled products - Under the Controlled Products Regulation, a controlled product is defined as a material, product or substance which is imported or sold in Canada and meets the criteria for one or more of the following classes:

Class A - Compressed gas

Class B - Flammable and combustible material

Class C - Oxidizing material

Class D - Poisonous and infectious material

Class E - Corrosive material

Class F - Dangerously reactive material

Corrosive material - A material that can attack (corrode) metals or cause permanent damage to human tissues such as skin and eyes on contact.

Cryogenics - Materials which exist at extremely low temperatures, such as liquid nitrogen.


Dangerously reactive materials- Materials that may undergo vigorous condensation, decomposition or polymerization. They may react violently under conditions of shock or increase in pressure or temperature. They may also react vigorously with water of water vapour to release a toxic gas.

Decomposition - The breakdown of a substance, often due to heat, decay, or other effect, with the release of other compounds such as vapours or gases that may be flammable or toxic.

Density - The weight of a material in a given volume. It is usually given in grams per millilitre (gm/ml).

Dilution ventilation - Dilution of contaminated air with uncontaminated aid in a general area, room or building for the purposes of health hazard or nuisance control, and/or for heating and cooling.

Dose - Amount of the agent that has entered the body through the various routes of entry.


Evaporation rate - The rate at which a liquid changes to vapour at normal room temperature.

Explosive (flammable) limits - The lower explosive (flammable) limit (LEL) is the lowest concentration of vapour in air which will burn or explode upon contact with a source of ignition. The upper explosive (flammable) limit (uel) is the highest concentration of vapour in air which will burn or explode upon contact with a source of ignition.

Explosive (flammable) range - The range between the lower explosive limit (LEL) and the upper explosive limit (UEL).

Exposure limits - Established concentrations which, if not exceeded, will not generally cause adverse effects to the worker exposed. Exposure limits differ in name and meaning depending on origin. For example:

  1. The exposure levels for the hazardous chemicals that are included in the Regulation respecting the Control of Exposure to Biological or Chemical Agents - made under the Occupational Health and Safety Act of Ontario, are expressed as follows:
    1. Time weighted average exposure value (TWAEV)- The average airborne concentration of a biological or chemical agent to which a worker may be exposed in a work day or a work week.
    2. Short term exposure value (STEV)- The maximum airborne concentration of a chemical or biological agent to which a worker may be exposed in any 15 minute period, provided that the TWAEV is not exceeded.
    3. Ceiling exposure value (CEV)- The maximum airborne concentration of a biological or chemical agent to which a worker may be exposed at any time.
    4. Skin- This notation indicates that direct or airborne contact with the product through the skin, mucous membranes or ears. Inclusion of this notation is intended to suggest that preventative action be taken against absorption of the agent through these routes of entry.
  2. Threshold limit values (TLVs) are exposure guidelines developed by the American Conference of Governmental Hygienists (ACGIH). They have been adopted by several Canadian governments and others as their legal limits. They are expressed as follows:
    1. Threshold limit value - Time weighted average (TLV-TWA)- concentration for a normal 8 hour work day and a 40 hour work week, to which nearly all workers may be repeatedly exposed, day after day, without adverse affect.
    2. Threshold limit value - Short term exposure limit (TLV-STEL) - A 15 minute time-weighted average exposure which should not be exceeded at any time during a work day even if the 8 hr TWA is within the TLV. Exposures at the STEK should not be repeated more than 4 times a day and there should be at least 60 minutes between successive exposures at the STEL.
    3. Threshold limit value-Ceiling (TLV-C)- The concentration that should not be exceeded during any part of the working exposure.


Flammable limits - See "explosive limits".

Flammable substance - One that will readily catch fire and continue to burn in air if exposed to a source of ignition.

  1. Flammable aerosol - A material that is packaged in an aerosol container which can release a flammable material.
  2. Flammable gas - A gas which can readily catch fire and continue to burn.
  3. Flammable liquid - A material that gives off a vapour which can readily catch fire and continue to burn. A flammable liquid has a flashpoint below 37.8°C.
  4. Flammable solid - A material which can readily catch fire and continue to burn vigorously and persistently. This may occur form friction, absorbing moisture, from spontaneous chemical change, or by retaining heat from manufacturing or processing.
  5. Reactive flammable material - A material which is a dangerous fire rick because it can react readily with air or water.

Flashback - This occurs when a trail of flammable material is ignited by a distant source of ignition. The flame then travels back along the trail of gas, vapour or aerosol to its source.

Flash point - The lowest temperature of a liquid at which it gives off enough vapour to form an ignitable mixture of vapour and air immediately above the surface of the liquid.

Freezing point - The temperature at which a liquid becomes a solid, at normal atmospheric pressure.


Hazard - the potential for harmful effects.

Hazardous combination products - Chemicals which may be formed when a material burns. These chemicals may be flammable, toxic or have other hazards.

Hazardous decomposition products - Formed when a material decomposes (breaks down) because it is unstable, or reacts with materials such as water or oxygen in air.

Hazardous ingredient - Under the Hazardous Products Act, a chemical must be listed in the Hazardous Ingredients section of an MSDS if:

  • It meets the criteria for a controlled product,
  • It is one of the ingredient disclosure list
  • There is no toxicological information available, or
  • The supplier has reason to believe it might be hazardous.

Hazardous polymerization - Polymerization is a process of forming a polymer by combining large numbers of chemical units or monomers into long chains (polyethylene from ethylene or polystyrene from styrene). Uncontrolled polymerization can be extremely hazardous. Some polymerization processes can release considerable heat or can be explosive.


Ingestion - Means taking a material into the body by mouth (swallowing).

Inhalation - Means taking a material into the body by breathing it in.

Irritant - Some sort of aggravation of whatever tissue the material comes in contact with.


LC50 - The concentration which causes the death of 50% of a group of test animals. The material is inhaled over a set period of time, usually 4 hrs. LC stands for lethal concentration.

LD50 - The weight of material which causes the death of 50% of a group of test animals. It is usually expressed in weight of material per weight of test animal. LD stands for lethal dose.

Lower Explosive Limit (LEL)- See "explosive limits".

Local exhaust ventilation - Involves the capture of pollutants at the source.


Material causing immediate and serious toxic effects- Classified under "Poisonous and infectious material" as toxic or very toxic based on information such as the LD50 or LC50.

Material causing other toxic effects- Classified under "Poisonous and infectious material" as a material causing toxic effects such as skin or respiratory sensitisation, carcinogenicity, mutagenicity, etc.

Melting point - The temperature at which a solid material becomes a liquid.

Mutagen - An agent that affects the genes or cells of the exposed people in such a way that it may cause cancer in the exposed individual or an undesired mutation to occur in some later generation.


North American (NA) number - See "United Nations number".


Odour threshold - The airborne concentration, usually in parts per million, at which an odour becomes detectable.

Oxidizing material - Gives up oxygen easily or can readily oxidize other material.


Permissible exposure limits (PEL) - Legal limits in the U.S.A. set by the Occupational Safety and Health Administration (OSHA).

pH - a measure of the acidity or alkalinity of a material when dissolved in water.

Polymer - A natural or man-made material formed by combining large numbers of chemical units or monomers into long chains.

Part per million (PPM) - Represents the concentration of gases or vapour in air. For example, 1 ppm of a gas means that 1 unit of the gas is present for every 1 million units of air.


Sensitization - The development, over time, of an allergic reaction to a chemical.

Solubility -The ability of a material to dissolve in water or another liquid.

Solvent - A material which is capable of dissolving another chemical.

Specific gravity - The density of a liquid compared to the density of an equal amount of water.

Stability - The ability of a material to remain unchanged in the presence of heat, moisture or air.


Teratogen - Agents or compounds that a pregnant woman takes into her body that generates defects in the fetus.

TLV - See "exposure limits".

Toxicity - Ability of a substance to cause harmful effects.

Trade name - The name under which a product is commercially known.

TWA - See "exposure limits".


Upper explosive limits (UEL) - See "explosive limits".

United Nations (UN) number - A four digit number assigned to a potentially hazardous material or class of materials. UN numbers are internationally recognized and are used by fire fighters and other emergency response personnel for identification of materials during transportation emergencies. North American (NA) numbers are assigned by Transport Canada and the US Department of Transport to materials they consider hazardous and to which a UN number has not been assigned.


Vapour - A gaseous form of a material which is normally solid or liquid at room temperature and pressure.

Vapour density - The density of a vapour compared to the density of an equal amount of air.

Vapour pressure - The pressure of a vapour in equilibrium with its liquid or solid form.

Ventilation - The movement of air.

Volatility - The ability of a material to evaporate.


WHMIS toxicity categories - The adverse (acute) effects resulting from a single dose of or exposure to a material. Ordinarily used to denote effects observed in experimental animals. WHMIS categorizes chemicals as "toxic" or "very toxic".

WHMIS class Descriptive term LD 50 wt/kg LC50 4 hr inhalation
Oral Skin Gas (ppk) Vapour (ppm) Dust (mg/L)
D Very toxic Below 50 mg Below 200 mg Below 2500 Below 1500 Below 0.5
Division 1
Subdivision A
D Toxic 50-500 200-1000   1500-2500 0.5 - 2.5
Subdivision B
  Essentially non-toxic Above 500 Above 1000 Above 2500 Above 2500 Above 2.5

Source: "WHMIS: What You Need To Know", Office of Environmental Health and Safety, University of Toronto. Reproduced with permission.

9-heading MSDS

The 9-heading MSDS contains the following information:

  1. Product information - Discloses manufacturer's and supplier's contact information, name of product and what it is used for.
  2. Hazardous ingredients - Lists the percentage concentrations of all regulated ingredients.
  3. Physical data - Contains information regarding the physical properties of the material such as density, boiling point, melting point, etc.
  4. Fire and explosion data - Reveals fire fighting measures, lower and upper explosive limits, autoignition temperatures, etc.
  5. Reactivity data - Lists the incompatible materials (if any) and conditions under which the material becomes unstable.
  6. Toxicological properties - Includes information concerning possible health effects and exposure limits.
  7. Preventative measures - The recommendations to avoid exposure.
  8. First aid measures - Specific first-aid measures to follow in case of exposure.
  9. Preparation information - Discloses contact information regarding group that prepared the MSDS and the date of preparation.

16-heading MSDS

The 16-heading MSDS contains the following information:

  1. Chemical product and company information
    1. Product name: Name of the product that matches the supplier label.
    2. Supplier name: Name, address and telephone number of the supplier.
    3. Validated/preparation date: Must not be older than three years. May also be found under "Other information".
    4. Product uses: Describes what the product is used for. If you wish to use it for other purposes, or product use is not indicated, contact your supervisor for clarification.
    5. Product classification: Indicates WHMIS class(es) that the product belongs to. May also be found under "Regulatory information".
  2. Composition/information on ingredients- Percent make-up of all hazardous ingredients will be listed here.
  3. Hazard identification- Provides an overview of known health effects. Details can be found in Toxicological Information.
  4. First aid measures - Describes first aid or medical treatment if exposure occurs.
  5. Fire-fighting measures - Details fire fighting methods, extinguishing media and hazardous products of combustion. Flammability data such as flash point, explosive limits and auto-ignition temperature will also be listed here.
  6. Accidental release measures - Provides information on how to clean up spills or accidental releases of hazardous materials.
  7. Handling and storage - Describes safe handling procedures to minimize exposure to hazardous materials and identifies incompatible storage conditions to be avoided.
  8. Exposure controls, personal protection and exposure limits - Contains recommendations that will help to make the working environment safe such as proper ventilation. Also lists the proper protective equipment that must be worn, such as gloves, eye protection, etc.. Exposure limits as established by various independent and regulatory agencies may also be found in this section.
  9. Physical and chemical properties - Details about the unique properties of the hazardous material can be found here to help determine safe handling procedures.
  10. Stability and reactivity - Information regarding the material's reactivity with other materials and what changes can occur during storage.
  11. Toxicological information - Provides information about the toxicity of the material and results of toxicity studies regarding the various routes of entry.
  12. Ecological information - Describes what effect the material may have on the environment and assist in determining proper disposal procedures.
  13. Disposal considerations - Provides information regarding treatment, recycling and disposal methods.
  14. Transport information - Information regarding transport regulations such as TDG class, packing group, PIN numbers and other special considerations when transporting the material.
  15. Regulatory information - This section lists applicable governmental regulations that pertain to the product. Various international regulations may also be found here.
  16. Other information - Additional information regarding the material may be found here such as references and contact information if the MSDS was prepared by an agency other than the manufacturer or supplier.

MSDS databases

Only MSDS, CHEMINFO, HSELINE, RTECS AND NIOSHTIC databases can be accessed by University of Waterloo users.

  Please direct inquiries to Doug Dye ext. 35613.