Globally Harmonized System (GHS) and How it Affects You

Globally Harmonized System (GHS)

Why is Global Harmonization Necessary?

Currently, many different countries have different systems for the 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?

The two major elements of GHS are:

  1. Classification 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, 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 that 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.
  • Precautionary Statement - These statements are standardized phrases that describe the recommended steps to be taken to minimize or prevent adverse effects from exposure to or resulting from improper handling or storage of a hazardous product.
  • 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.


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 classes:

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


Where Can I Get Information on the GHS Criteria for the Different Hazard Casses?

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 Labelling of Chemicals (GHS)from the United Nations Economic Commission for Europe (UNECE).

GHS is a dynamic system. The international GHS committee meets twice a year to work on developing potential new hazard classes as well as resolving specific issues, and updating the latest GHS publication. Check the above link for more information.

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 Hazardous Products Regulations were published in Canada Gazette, Part II on February 11, 2015. Both the amended Hazardous Products Act and new regulations are currently in force. "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.

Note that the provincial, federal, and territorial occupational health and safety WHMIS regulations will also require updating.

A multi-year transition plan has been announced. From now until May 31, 2017 suppliers (manufacturers and importers) can use WHMIS 1988 or WHMIS 2015 to classify and communicate the hazards of their products (suppliers must use one system or the other). Beginning June 1, 2017, to May 31, 2018, distributors and suppliers importing for their own use can continue to use WHMIS 1988 or WHMIS 2015.


GHS has been adopted into the new EU Classification, Labelling and Packaging (CLP) regulations (in force as of January 20, 2009). These regulations must be used for new products, which are:

  • Pure substances by December 1, 2010.
  • Mixtures by June 1, 2015.

There is a two-year transition period for existing products labelled and packaged according to EU Directives (67/548/EEC and 1999/45/EC, both as amended).

United States

Final Rule became effective May 26, 2012. Key dates in the US implementation include:

  • December 1, 2013 - Train employees on the new label elements and SDS format.
  • June 1, 2015 - Comply with all modified provisions of the final rule, except December 1, 2015 - Distributors may ship products labelled by manufacturers under the old system until December 1, 2015.
  • June 1, 2016 - Update alternative workplace labelling and hazard communication program as necessary, and provide additional employee training for newly identified physical or health hazards.
  • Transition Period - Comply with either 29 CFR 1910.1200, or the current standard, or both.

Adapted from:  Hazard Communication Standard Final Rule, OSHA Fact Sheet (2012)

Other Countries

To find out more about the status of GHS implementation in other countries and their sectors, please see the article produced by the UNECE.

How Will GHS Change WHMIS?

Overall, the current roles and responsibilities for suppliers, employers and workers have not changed in WHMIS 2015.

Suppliers, Importers and Producers duties 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 still must:

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

Again, please note:  This document discusses the global GHS system, as developed by the United Nations. GHS is a 'non-binding' system of hazard communication. Only the elements of GHS that have been explicitly adopted by Canadian legislation are enforceable.  See the OSH Answers documents on WHMIS 2015 for a summary of how GHS was implemented in Canada.

Where Can I Get More Information?

Information from across Canada is available on the website

Also, the Canadian Centre for Occupational Health and Safety (CCOHS), in partnership with Health Canada, has developed free on-line training courses to help workers and workplaces prepare for WHMIS 2015.

WHMIS 2015 for Workers (60 minutes)
Learn about WHMIS after its alignment with GHS, an internationally consistent approach to classifying chemicals and communicating hazard information through labels and safety data sheets (SDSs).

WHMIS After GHS: An Introduction (30 minutes)

WHMIS After GHS: How Suppliers Can Prepare (60 minutes)

These courses are offered in English and French and are free of charge.

Health Canada also offers an email news service to announce information about WHMIS.

Document last updated on March 10, 2015

Leave a comment

and join the conversation

Your email address will not be published. Required fields are marked *