Title Graphic for The Global Harmonized System Article showing a large stack of papers

The Global Harmonized System (GHS)

The GHS is short for the Globally Harmonized System of Classification and Labeling of Chemicals. The GHS is an internationally recognized system for classifying and labeling hazardous chemicals. It was developed by the United Nations in order to promote the safe use and handling of hazardous chemicals worldwide by creating a standardized system for communicating chemical hazard information.

The GHS is based on the principle that hazard classification and communication should be consistent across different countries and regions. It provides a standardized approach to classifying hazardous chemicals and it specifies the types of labeling and safety data sheet (SDS) information that should be provided for each class of chemical.


The current edition of the GHS reference manual is Rev9, published in 2021.

The manual is conveniently located for free download on the United Nations Economic Commission for Europe (UNECE) Website here.

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GHS Implementation

The GHS itself is not a regulation and is not directly enforced by a regulatory body. Enforcement associated with GHS-compliant documents is only done when the GHS system is incorporated into legal codes by regulatory agencies.

For American businesses, the most relevant enforcement agencies are the Department of Labor's Occupational Safety and Health Administration (OSHA), the Department of Transportation's Pipeline and Hazardous Material Safety Administration (PHMSA), and the Department of Interior's Environmental Protection Agency (EPA). All of these United States Federal Departments have GHS system elements within their regulations, including the use of signal words, precautionary statements, and standardized pictograms.

What Does the GHS Cover?

The GHS provides a framework for the standardization of hazard communication as it relates to classifying chemicals and communicating that classification, with the reference document being in 4 Parts, plus a set of Annexes.

Part 1 - Introduction

The Introduction covers the purpose, scope, and application of the GHS. It also gives an overview of the classification of hazardous substances and the guidelines for Hazard Communication labels and safety data sheets.

Part 2 - Physical Hazards

The Physical Hazards section provides standardized definitions of physical hazards, which are properties that can affect the immediate physical environment where the chemical is located. These include Explosives, Flammable Liquids, and Organic Peroxides.

Part 3 - Health Hazards

The Health Hazards section provides standardized definitions of health hazards, which are properties that can have adverse effects on human health. These include Acute Toxicity, Respiratory or Skin Sensitization, and Carcinogenicity.

Part 4 - Environmental Hazards

The Environmental Hazards section provides standardized definitions of environmental hazards, which are properties that can have adverse effects on the environment and wildlife. These are Hazards to the Aquatic Environment and hazards to the Ozone Layer.


The Annexes are the primary reference guide for implementing hazard communication following the GHS. They include decision trees with reference to the UN Manual of tests to determine if a given chemical qualifies under a GHS hazard class. They also include guidance on the preparation of GHS-compliant Safety Data Sheets (SDS) and examples of GHS-compliant labels, including appropriate signal words, hazard statements, and GHS pictograms.

Importance of the GHS

Since its first publication in 2003, GHS has been an important aspect of safety in global trade. Understanding the contents of the GHS and how both local trade regulations and international trade regulations have incorporated the system is an important part of maintaining good hazard communication practices.

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