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GHS began as an idea over three decades ago about how to improve communication of chemical hazards and better protect employees and other end users of chemical products. Today, GHS is more than an idea, having been implemented or partially implemented in some 67 countries. 

Much ground still needs to be covered for GHS to be fully realized as conceived back in 1992; nevertheless, as the following timeline demonstrates, the strength of the original idea has sustained the development of GHS through decades and with some recent successes, it appears to be gaining momentum.

History of GHS


  • OSHA issues Hazard Communication Standard (HCS) covering only the manufacturing industry. 
  • First HCS preamble recommends an internationally harmonized system: “The development of internationally agreed standards would make possible the broadest recognition of the identified hazards while avoiding the creation of technical barriers to trade and reducing the costs of dissemination of hazard information by elimination of duplicative requirements which could otherwise apply to a chemical in commerce.” 


  • OSHA revised HCS, expanding it to cover all industries where employees are potentially exposed to hazardous chemicals. 


  • OSHA issues Request for Information (RFI) on international harmonization efforts and the work being done by International Labor Organization (ILO) on chemical safety at work. 
  • OSHA issues RFI on HCS, including the idea of a standard SDS format. The majority of respondents support standardized SDSs and labels. 


  • United Nations holds U.N. Conference on Environment and Development (UNCED) in Rio de Janeiro, also known as the “Earth Summit.” UNCED issues mandate (supported by U.S.) calling for the development of a globally harmonized chemical classification and labelling system. 
  • The 1992 UNCED mandate reads: “A globally harmonized hazard classification and compatible labelling system, including material safety data sheets and easily understandable symbols, should be available, if feasible, by the year 2000.” 
  • Multinational coordinating group is established called the Inter-Organization Programme for the Sound Management of Chemicals Coordinating Group for the Harmonization of Chemical Classification Systems. OSHA serves as chair of this group. 
  • Work is divided into three parts: 
    • 1. Classification criteria for physical hazards – Developed by the United Nations Subcommittee of Experts on the Transport of Dangerous Goods/ International Labour Organization working group 
    • 2. Classification criteria for health and environmental hazards – Developed by the Organization for Economic Cooperation and Development 
    • 3. Hazard communication elements (including SDSs and labels) – Developed by the International Labour Organization 
  • Four major existing programs serve as basis for GHS: 
    • 1. U.S. requirements for the workplace, consumers and pesticides. 
    • 2. Canadian requirements for workplace, consumers and pesticides 
    • 3. European Union directives for classification and labelling of substances and preparations 
    • 4. United Nations recommendations on the Transport of Dangerous Goods 
  • Key guiding principle of the harmonization work: 
    • 1. Protections of the existing systems would not be reduced as a result of GHS 
    • 2. Will be based on intrinsic properties (hazards) of chemicals 
    • 3. All types of chemicals will be covered 
    • 4. All systems will have to be changed 
    • 5. Involvement of all stakeholders should be ensured 
    • 6. Comprehensibility must be addressed 
  • OSHA, DOT, CPSC and EPA formed Interagency Working Group on Harmonization to work in concert with the State Department to represent the United States’ interest in the GHS process. 


  • United Nations renamed the UNCEDTG to the Committee of Experts on the Transport of Dangerous Goods and on the Globally Harmonized System of Classification and Labelling of Chemicals (UNCETDG/GHS). 
  • Two subcommittees are created for UNCETDG/GHS; one on transport, and one called the Sub-Committee on the Globally Harmonized System of Classification (UNSCEGHS). 
  • The UNSCEGHS was designated as being responsible for maintaining the GHS and promoting its implementation. 


  • At the World Summit on Sustainable Development (WSSD), countries were encouraged to adopt GHS by 2008. 
  • GHS formally adopted by the UNCETDG/GHS. 


  • GHS adoption is endorsed by the Economic and Social Council of the United Nations. 
  • First edition of the GHS “purple book” is published. 


  • EPA’s Office of Pesticide Programs drafted White Paper on EPA’s initial thinking on GHS and how it might be applied to pesticide labels. 


  • OSHA added the adoption of GHS and the modification of the HCS to its regulatory agenda. 
  • First revised edition of GHS is published and includes amendments adopted by Committee of Experts. 


  • OSHA published Advanced Notices of Proposed Rulemaking (ANPR) on GHS. 


  • Second revised edition of GHS is published. 
  • DOT adopted many aspects of GHS that directly deal with the transport sector, such as changes to the hazard classification criteria for toxic materials and flammable liquids. 
  • DOT held off on rulemaking for regulations concerning environmentally hazardous substances, and decided to await further consideration on the topic by the EPA. 


  • Third revised edition of GHS is published.
  • OSHA proposed modifications to the HCS to align with GHS. 


  • U.S. hosted public hearings on GHS and OSHA’s proposed rulemaking. 
  • GHS currently implemented or in various stages of implementation in 67 countries. 


  • OSHA delivered final rule to the Office of Management and Budget (OMB) – October 25 
  • OSHA met with OMB and a series of stakeholders to discuss several issues such as combustible dust and compliance time frame. November – January. 


  • OMB passed final rule on GHS in February with the designation: “Consistent with Change.” The final rule aligned the HazCom Standard with Revision 3 of the GHS. 
  • OSHA announced the final rule. Dr. David Michaels, then serving as Assistant Secretary of Labor for OSHA, called it HazCom 2012 and said it goes beyond “Right to Know” and gives workers the “Right to Understand.” The final rule revising HazCom is published in Federal Register on March 26, with an effective date set for 60 days after publication, although there would be a phased-in compliance timeline running until 2016. 


  • December 1 – This was the deadline established for employers to have completed training of employees on how to read GHS formatted safety data sheets and labels. 


  • June 1 – This was the original deadline for manufacturers and distributors to have complied provisions of the revised HCS. This included reclassifying chemicals and producing GHS aligned labels and SDSs. Distributors received additional 6 months to distribute old inventory already labelled in accordance with previous requirements. 
  • December 1 – This was the deadline for distributors to have fully complied with revised HCS. (Grace period ends.) 


  • June 1 – This was the deadline for employers to have fully complied with revised HCS and complete training of employees on newly identified hazards and/or any updates to workplace hazard program. 


  • UN published GHS Revision 7. 


  • UN published GHS Revision 8. 


  • UN published GHS Revision 9.
  • OSHA published a proposed rule to update the HazCom Standard to align with GHS Revision 7.


  • Canada publishes final rule updating Hazardous Product Regulations (HPR) to align with GHS Revision 7 and select elements of Revision 8.
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