GHS FAQ – Frequently Asked Questions

What is the Globally Harmonized System (GHS)?

GHS Label RollGHS stands for the Globally Harmonized System of Classification and Labeling of Chemicals. GHS is a system that defines and classifies the hazards of chemical products, and communicates health and safety information on labels and material safety data sheets (called Safety Data Sheets, or SDSs, in GHS). The goal is that the same set of rules for classifying hazards, and the same format and content for labels and safety data sheets (SDS) will be adopted and used around the world. An international team of hazard communication experts developed GHS.

Why is global harmonization necessary?

Currently many different countries have different systems for classification and labelling of chemical products. In addition, several different systems can exist even within the same country. This situation has been expensive for governments to regulate and enforce, costly for companies who have to comply with many different systems, and confusing for workers who need to understand the hazards of a chemical in order to work safely.

GHS promises to deliver several distinct benefits. Among them are:

  • Promoting regulatory efficiency
  • Facilitating trade
  • Easing compliance
  • Reducing costs
  • Providing improved, consistent hazard information
  • Encouraging the safe transport, handling and use of chemicals
  • Promoting better emergency response to chemical incidents
  • Reducing the need for animal testing

What is the scope of GHS?

The GHS system covers all hazardous chemicals and may be adopted to cover chemicals in the workplace, transport, consumer products, pesticides and pharmaceuticals. The target audiences for GHS include workers, transport workers, emergency responders and consumers.

What are the two major elements in GHS?

1. GHS Label ExampleClassification of the hazards of chemicals according to the GHS rules:

GHS provides guidance on classifying pure chemicals and mixtures according to its criteria or rules.

2. Communication of the hazards and precautionary information using Safety Data Sheets and labels:

Labels – With the GHS system, certain information will appear on the label. For example, the chemical identity may be required. Standardized hazard statements, signal words and symbols will appear on the label according to the classification of that chemical or mixture. Precautionary statements may also be required, if adopted by your regulatory authority.

Safety Data Sheets (SDS) – The GHS SDS has 16 sections in a set order, and minimum information is prescribed.

What are some key terms in the GHS Vocabulary?

SDS – Safety Data Sheet. SDS is the term used by GHS for Material Safety Data Sheet (MSDS).

Hazard Group – While not given a formal definition, GHS divides hazards into three major groups – health, physical and environmental.

Class – Class is the term used to describe the different types of hazards. For example, Gases under Pressure is an example of a class in the physical hazards group.

Category – Category is the name used to describe the sub-sections of classes. For example, Self-Reactive Chemicals have 7 categories. Each category has rules or criteria to determine what chemicals are assigned to that category. Categories are assigned numbers (or letters) with category 1 (or A) being the most hazardous.

Hazard Statement – For each category of a class, a standardized statement is used to describe the hazard. For example, the hazard statement for chemicals which meet the criteria for the class Self-heating substances and mixtures, Category 1 is Self-heating; may catch fire. This hazard statement would appear both on the label and on the SDS.

Signal Word – There are two signal words in the GHS system – Danger and Warning. These signal words are used to communicate the level of hazard on both the label and the SDS. The appropriate signal word to use is set out by the classification system. For example, the signal word for Self-heating substances and mixtures, Category 1 is Danger while Warning is used for the less serious Category 2. There are categories where no signal word is used.

Pictogram – Pictogram refers to the GHS symbol on the label and SDS. Not all categories have a symbol associated with them.

What is meant by the GHS hazard groupings and building block concept?

Within the GHS classification system, there are three major hazard groups:

  • Physical hazards
  • Health hazards
  • Environmental hazards

Within each of these hazard groups there are classes and categories. Each of these parts is called a building block. Each country can determine which building blocks of the GHS system it will use in their different sectors (workplace, transportation, consumers). Once the building blocks are chosen, the corresponding GHS rules for classification and labels must be used.

What are the classes within the Health hazard group?

Criteria for classifying chemicals have been developed for the following health hazard classes:

  • Acute toxicity
  • Skin corrosion/irritation
  • Serious eye damage/eye irritation
  • Respiratory or skin sensitization
  • Germ cell mutagenicity
  • Carcinogenicity
  • Reproductive toxicity
  • Specific target organ toxicity – single exposure
  • Specific target organ toxicity – repeated exposure
  • Aspiration hazard

In addition, there are specific classification rules for chemical mixtures for each health hazard class.

What are the classes within the Physical hazard group?

Criteria for classifying chemicals have been developed for the following physical hazard classes:

  • Explosives
  • Flammable gases
  • Aerosols
  • Oxidizing gases
  • Gases under pressure
  • Flammable liquids
  • Flammable solids
  • Self-reactive substances and mixtures
  • Pyrophoric liquids
  • Pyrophoric solids
  • Self-heating substances and mixtures
  • Substances and mixtures which, in contact with water, emit flammable gases
  • Oxidizing liquids
  • Oxidizing solids
  • Organic peroxides
  • Corrosive to metals

What are the classes within the Environmental hazard group?

Criteria for classifying chemicals have been developed for the following environmental hazard class:

  • Hazardous to the aquatic environment (acute and chronic)
  • Hazardous to the ozone layer

In addition, there are specific classification rules for chemical mixtures for each environmental hazard class.

Where can I get information on the GHS criteria for the different hazard classes?

The most current information on GHS classification, labels and SDS as well as other criteria is available in the 5th revised edition* of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) from the United Nations Economic Commission for Europe (UNECE).

What is the target date for implementation of GHS?

Countries and sectors (consumer, environmental, workplace, transportation) within a country will implement GHS at varying times depending on their local circumstances.


The Globally Harmonized System for Classification and Labeling of Chemicals (GHS) is being implemented by Canada and this alignment will change WHMIS-related laws (the Hazardous Products Act and Controlled Products Regulations).

Health Canada is the government body responsible for making the required changes to the WHMIS related laws. Final regulations are expected to be published in the Canada Gazette Part II in 2014. Health Canada’s goal is to have the updated WHMIS laws in force by 2015 or later. In force means that suppliers may begin to use and follow the new requirements for labels and SDSs for hazardous products sold, distributed, or imported into Canada at that time. A transition period is expected, but the dates have not yet been announced. Please check this site regularly for updates.

Provincial and territorial WHMIS regulations will also require updating. It is expected that jurisdictions will complete this update by June 2016. Employers will be expected to have updated their WHMIS program and training to include the alignment with GHS at this time (exact timelines to be determined).

How will GHS change WHMIS?

Roles and Responsibilities

Overall, the current roles and responsibilities for suppliers, employers and workers likely will not change in WHMIS after GHS.

Suppliers, Importers and Producers duties will continue to include:

  • Classifying hazardous products
  • Preparing labels and SDSs
  • Providing these elements to customers

Employers must continue to:

  • Educate and train workers on the hazards and safe use of products
  • Ensure that hazardous materials are properly labelled
  • Prepare workplace labels and SDSs as necessary
  • Provide access for workers to up-to-date SDSs
  • Ensure appropriate control measures are in place to protect the health and safety of workers

Workers will still:

  • Participate in WHMIS and chemical safety training programs
  • Take necessary steps to protect themselves and their coworkers
  • Participate in identifying and controlling hazards


How chemicals are classified will be affected. It is likely (but not confirmed) that WHMIS legislation will:

  • Adopt all of the major GHS health and physical hazard classes including aspiration hazard and specific target organ toxicity-single exposure. Some categories in GHS may not be adopted. It is unlikely that the environmental hazard classes will be adopted under WHMIS (but this does not exclude that it may be adopted by another government department).
  • Continue to include some hazards that are currently not in the GHS system, but are present in the current WHMIS system – such as biohazardous infectious materials.
  • Have more specific names for its hazard classes.
  • Combine two WHMIS classes (teratogenicity/embryotoxicity and reproductive toxicity) into one new GHS hazard class called reproductive toxicity.

Supplier labels

GHS Label ExampleLabels requirements will also change, and will probably have a few new requirements. Labels will use new pictograms, as well as a signal word – Warning or Danger. Under the GHS system, once a chemical is classified, specific signal words, hazard statements and pictograms are required (prescribed) for each hazard class and category. These elements must appear on the label.

All of the required elements for labels are not yet determined. It is still not clear, for example, if the names of hazardous ingredients will be included on the label, or if the WHMIS hatched border will still be required.

Currently in Canada, GHS labels do not meet WHMIS requirements. Employers should contact suppliers to request WHMIS labels if the WHMIS version of a label is not supplied with the product.

Safety Data Sheets (SDS)

SDSs will use a 16-section format. There will be standardized information requirements for each section. The 9-section WHMIS format for MSDSs will no longer be acceptable. Another important change to note is that the product classification and some of the label information will probably be required on the SDS. It has not been determined if the SDS updating requirements (every 3 years) will be kept; however, SDSs must be updated as new information comes available.

Health Canada has announced an administrative policy which allows a properly prepared and formatted GHS Safety Data Sheet (SDS) to be used in Canada at this time. All of the information required by the 9-section Canadian MSDS must be listed on the GHS SDS.

Material safety data sheets – Format
The information requirements of Canadian 9-heading SDS (Schedule I, Column III of the Controlled Products Regulation) can be found here:

Schedule I – Information to be Disclosed on a Material Safety Data Sheet, Reference Manual for the WHMIS Requirements of the Hazardous Products Act and Controlled Products Regulations

Note that there are additional Canadian requirements for MSDSs/SDSs which must continue to be met at this time, for example:

  • The SDS must be available in English and French
  • The SDS must not have a preparation date exceeding 3 years
  • The SDS must provide the name and address of a Canadian supplier
  • Hazardous ingredients must be disclosed according to the requirements of the Hazardous Products Act

How can suppliers prepare now?

Under WHMIS after GHS, suppliers will continue to classify products, create labels and create SDSs (formerly MSDSs) but they will follow the WHMIS after GHS requirements.

To prepare to classify a product, suppliers could:

  1. Obtain a copy of the GHS criteria
  2. Identify the relevant hazard data for their ingredients and products
  3. Review the data in light of the classification criteria to determine the appropriate hazard classes and categories. Note that there is specific guidance for classifying the health and environmental hazards of mixtures
  4. Document the rationale and information for future reference

Once changes to WHMIS legislation have been published, confirm product classifications.

Suppliers must use a weight of evidence approach to classify products. The validity of research reports and other information must be evaluated as a whole. In some cases a single, well-conducted study will be sufficient.

If they are not already doing so, suppliers could also switch to a 16-section SDS format.

How can employers prepare now?

After GHS implementation, SDSs and labels for products originating within and outside of Canada will share common elements. This standardization should simplify education and training after the transition period is over. However employees will need training on both systems until the transition is complete.

Keeping up-to-date inventories of all controlled products and the status of the MSDS/SDS will be essential.