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Becoming an expert on the GHS requires a significant investment of time. The good news is that you probably won’t need to become an expert on every aspect of the system, but safety professionals can certainly benefit from a comprehensive overview.  

OSHA anticipates it will take the average safety professional approximately 8 hours to get comfortable with the new standard. To help, we have created a condensed version of the GHS Third Revision (GHS R3) that provides a thorough, yet easy-to-understand introduction to the GHS.  

As you read, you will likely identify aspects of the GHS that are applicable to your specific duties. You are encouraged to investigate those aspects in greater depth using the source materials for this overview.  

If you have questions, check out our GHS Facts section or contact us today.

What is the GHS and Who Developed It? 

GHS stands for the Globally Harmonized System of Classification and Labelling of Chemicals. 

Developed by the United Nations, the premise of the GHS is that existing chemical classification and labelling systems (such as OSHA’s Hazard Communication Standard (HCS)) “should be harmonized in order to develop a single, globally harmonized system to address classification of chemicals, labels and safety data sheets.” 

Born out of the 1992 Earth Summit – the UN Conference on Environment and Development (UNCED) – in Rio de Janeiro, the GHS was expressly called for in the UNCED’s ‘International Mandate,’: 

“A globally harmonized classification and compatible labelling system, including material safety data sheets and easily understandable symbols, should be available, if feasible, by the year 2000.” 

Work on the GHS was carried out on behalf of the U.N. by several agencies and committees until 2001 when oversight was given to the United Nations Committee of Experts on the Transport of Dangerous Goods and the Globally Harmonized System of Classification and Labelling of Chemicals (UNCETDG/GHS). That’s a mouthful. 

The UNCETDG/GHS has two sub-committees which handle the technical aspects of the GHS. The  Sub-Committee of Experts on the Transport of Dangerous Goods (UNSCETDG). And the Sub-Committee of Experts on the Globally Harmonized System of Classification and Labelling of Chemicals (UNSCEGHS). 

The UNSCEGHS is responsible to: 

  1. Act as the custodian of GHS and the harmonization process 
  2. Keep GHS up-to-date as necessary 
  3. Promote understanding and encourage feedback 
  4. Make GHS available for worldwide use and application 
  5. Make guidance available on the application of GHS 
  6. Prepare work programs and submit recommendations to the committee 

In 2002, the World Summit on Sustainable Development called for global adoption of the GHS by 2008. 

In 2003 the UNSCEGHS published the first version of the GHS. Any given edition of the GHS is commonly known as the “purple book.” 

Since 2003, the GHS has been revised every two years, with the latest version published in 2021 (GHS R9). The following information is culled primarily from  GHS R3, which is at the current time still the edition of the GHS that OSHA’s HazCom Standard is aligned with.

Governments, regional institutions and international organizations are the primary audience for the GHS.  Still, it contains enough information and guidance for those charged with its implementation. 

The UNSCEGHS believes “widespread availability of information on chemicals will provide the foundation for national programs for safe management of chemicals and lead to safer conditions for the global population and the environment,” and that “it will also facilitate international trade by promoting greater consistency in the national requirements for chemical hazard classification and communication.” 

Why Have the GHS? 

Given the large number of hazardous chemicals in the world, the ability of one agency to effectively regulate them all is impractical if not impossible. In essence, each country or organization is on its own. 

Many countries and organizations have established laws and regulations requiring information to be prepared and transmitted through labels and/or safety data sheets to those people using or handling hazardous chemicals. 

While most of the laws and regulations put in place by local, state, national and international agencies are similar – their differences can be significant enough to require different labels and SDSs to be produced for the same chemical depending upon where it is used or who is using it. 

Inconsistencies between national and international laws create a regulatory and compliance nightmare that at best disrupts commerce and at worst compromises safety. 

More alarming, some countries have no system at all. 

These facts combined with the growth in global trade of chemicals form the need for an “internationally harmonized approach to the classification and labelling of chemicals.” 

By standardizing the components of dissimilar systems, the GHS protects workers, consumers, emergency responders, the environment and the public by creating a comprehensive system through which chemical hazards are identified and communicated to all who are potentially exposed. 

Additionally, global adoption of GHS is expected to reduce costs and inefficiencies associated with the international trade of chemicals. 

GHS is expected to: 

  1. Enhance the protection of human health and the environment by providing an internationally comprehensible system for hazard communication 
  1. Provide a recognized framework for those countries without an existing system 
  1. Reduce the need for testing and evaluation of chemicals 
  1. Facilitate international trade in chemicals whose hazards have been properly assessed and identified on an international basis 

How Was the GHS Developed? 

As a result of the 1992 “International Mandate,” work on the GHS was carried out on behalf of the U.N. by a multinational coordinating group called the Interorganization Programme for the Sound Management of Chemicals (IOMC) Coordinating Group for the Harmonization of Chemical Classification Systems (CG/HCCS). 

The scope of the original mandate called for two elements: 1) Harmonized criteria for classifying substances and mixtures according to their health environmental and physical hazards; and 2) harmonized hazard communication elements, including requirements for labelling and safety data sheets. 

Participation by US Agencies 

An Interagency Working Group corralled by the U.S. State Department and comprised of four U.S. agencies represented the U.S. in the creation of the GHS, the four agencies were: 

  • OSHA 
  • The Department of Transportation (DOT) 
  • The Environmental Protection Agency (EPA) 
  • Consumer Product Safety Commission (CPSC) 

OSHA served as the lead agency for the U.S. on the classification of chemicals and hazard communication. 

Principles for Developing the GHS: 

The primary task for the committees and agencies working on the GHS was to take the best aspects of existing systems and develop a harmonized approach using the following principles. 

  1. Level of protection should not be reduced in any system 
  2. Hazard classification based on intrinsic properties of substances and mixtures, whether natural or synthetic 
  3. All types of chemicals covered 
  4. All systems will have to be changed 
  5. Involvement of all stakeholders should be ensured 
  6. Comprehensibility must be addressed 
  7. Existing data about chemicals and methods for testing chemicals should be accepted and adapted 
  8. Confidential Business Information (CBI) should be protected as prescribed by competent authorities 

Four major systems were used as the primary basis of the GHS: 

  1. Requirement of systems in the United States for the workplace, consumers and pesticides 
  2. Requirements of Canada for the workplace, consumers and pesticides 
  3. European Union (EU) directives for classification and labelling of substances and preparations 
  4. UN recommendations on the Transport of Dangerous Goods 

In developing the GHS, it was agreed that it would cover all hazardous chemicals and that various forms of testing would be accepted; it was also agreed that it would not establish uniform test methods or harmonize risk assessment procedures or decisions (i.e. permissible exposure limit for employee exposure). 

How is the GHS Applied? 

According to the GHS R3, the goal of the GHS is to identify intrinsic hazards found in substances and mixtures and to convey hazard information about these hazards. 

It is also designed to allow the hazard communication elements of the existing systems to converge. 

To accomplish this, the criteria for hazard classification are harmonized and hazard statements, symbols, and signal words have been standardized and harmonized, forming an integrated hazard communication system. 

This doesn’t mean every agency needs to adopt the GHS in exactly the same way. Different agencies can align their regulations with different versions of the GHS, and even then, they can choose to adopt only those aspects of the GHS edition they find most pertinent, and include aspects of their own existing regulations that were not in that edition of the GHS.

Following are three examples. 

  • For transport, the GHS will be similar to current transport requirements. Containers will be marked with pictograms that address acute toxicity, physical hazards, and environmental hazards. Signal words and hazard statements are not expected to be adopted in the transport sector 
  • In the workplace, all GHS elements are expected to be adopted, including labels that have harmonized core information and safety data sheets, and it is expected such information will be supplemented by employee training 
  • For consumers, labels are expected to be the primary focus 

Is it a Global Law? 

A major concern many people have upon first learning about the GHS is that it is a global law encroaching upon the sovereignty of their own country. This common misconception is false. 

The GHS is not a global law or regulation; it is a system or a set of recommendations. 

The GHS uses a “building block” approach and no country is obligated to adopt all or even any part of the GHS. 

Countries are free to determine which of the building blocks will be applied in different parts of their system. However, where a country’s system incorporates a GHS building block, that coverage should be consistent. 

In other words, the GHS may be seen as a collection of building blocks from which to form a regulatory approach. 

It is hoped that the application of GHS worldwide will eventually lead to a fully harmonized situation. 

Building Block Approach Explained 

We get a better understanding of the building block approach by looking at specific examples of its application. 

One element of the GHS is the hazard class – which means the nature of the physical, health or environmental hazard, e.g. flammable solid, carcinogen, oral acute toxicity. In the GHS, hazard classes are building blocks. Competent authorities may choose which hazard classes they adopt. 

Furthermore, within hazard classes are hazard categories – which compare hazard severity within a hazard class. These categories are also building blocks and competent authorities have the possibility not to adopt all categories. 

However, if a hazard class or hazard category is adopted, then the GHS requests that certain aspects be followed within that class or category. 

For instance, when a hazard category is adopted, all the categories for higher hazard levels in that hazard class should also be adopted. So if a hazard class has four categories, if the level three hazard category is chosen, then levels one and two should also be chosen. 

With the harmonized classification criteria and hazard communication elements, the GHS is designed to accommodate self-classification and allow the uniform development of national policies, while remaining flexible enough to accommodate any special requirements that need to be met. 

The GHS is intended to be user-friendly and help reduce administrative burdens. 

If you would like to explore the GHS in great depth or get more detailed information on specific topic, you can read the Third Revised Edition of the GHSon the United Nations Economic Commission for Europe’s website. 

GHS Resource Center