“The Globally Harmonized System of Chemical Classification and Labelling” (GHS) was developed by the United Nations. GHS is an internationally agreed upon system with consistent criteria created to replace the many different hazard classification and labeling systems used in countries around the world.

International trade in chemicals is extensive. The many different hazard classification and communication systems used around the world resulted in multiple standards requiring multiple labels and safety data sheets for the same hazard in different countries. A worldwide approach was clearly needed. GHS is a voluntary framework for replacing the varied systems with a with a united global approach. Participating countries are provided with harmonized building blocks to implement their own hazard classification and communication system. For many countries GHS presents an opportunity to create an effective system at less cost than they could do on their own.


The United nations monitors the progress of international implementation of GHS. Implementation is voluntary and there is no set date for implemention of GHS. The European Union has implemented GHS standards into their regulations. In the United States, the Occupational Safety and Heath Administration (OSHA) is in the process of implementing GHS and has submitted a final rule to the Office of Management and Budget revising the Hazard Communication Standard to align with GHS.

Training will be needed when implementing GHS. Training is a key component of GHS. Employees, emergency responders and other will need appropriate training regarding GHS hazard classifications and their related symbols, pictograms, signal words, hazard and precautionary statements.

Hazard Classification

Hazard classification under GHS involves identifying chemical hazards using defined criteria to assign a “hazard class”. Only the intrinsic hazardous properties of chemicals are considered in classification. Classification processes include identifying relevant data, reviewing data to determine associated hazards, and making a decisions regarding the proper classification and hazard degree by comparing the data with the GHS hazard classification criteria. GHS avoids duplicating testing by allowing acceptance of data already generated for chemical classification under existing systems. Once a hazard classes has been determined, hazards are further divided into “hazard categories” to compare severity of hazards within the class.

Hazard classification include “Physical Hazards” such as Explosives, Flammable Gas, Self-Reactive Substances and Oxydizing Solids.; “Health Hazards” such as Acute Toxicity, Skin Corrosion, Carcinogenicity, and Aspiration Hazard; and “Environmental Hazards” such as Acute Aquatic Toxicity and Chronic Aquatic Toxicity.

Hazard Communication

After hazard classification is completed, the hazard information needs to be effectively commnicationed to the target audience. GHS established guiding principles for hazard communcation: Hazard information should be available in more than one form. Protection of users, consumers and the environment should not be compromised due to non-discloure of 'Confidential Business Information'. Hazard and precautionary statements should be included. Information should be harmonized and easy for the target audience to understand. Hazard phrases should be consistent.

Global harmonization is complex. Comprehensibility is challenging, even within the same country. Concerning factors in the development of GHS communication tools included differences in existing systems on exacty what and how hazard information should be communicated, the ability to translate phrases meaningfully, and the ability to understand and appropriately respond to the symbols and pictograms. GHS Label Elements Chemical labeling is regulated differently around the world resulting in the need for many different labels, with different looks, for the same chemical, leading to confusion and increased compliance burdens. GHS label elements include harmonized elements that are standardized for greater comprehensibility and understanding. GHS standardized elements such as symbols/pictograms, signal words, and hazard statements are not to be varied, and should appear on GHS labels without change or alteration. A harmonized approach to safety labeling helps to reduce compliance burdens and helps to ease global implementation of GHS..

GHS standardized label elements include the following:

  • Symbols / Pictograms are assigned to GHS hazard classes and categories. Pictograms have the harmonized hazard symbols incorporated with graphic elements used to convey specific information, such as borders, background colors or patterns.
  • Signal Words are assigned to GHS hazard classes and categories with the exception of a few catergories that have low hazard levels. GHS uses the signal words "Danger" or "Warning". When there are multiple hazards, the signal word assigned to the most severe hazard is used.
  • Hazard Statements are assigned to hazard classes and categories. When there are multiple hazards, appropriate statements for each hazard should be incl+uded on the label.
  • Other GHS label elements include:

    • Precautionary Statements addressing prevention, response to spillage or exposure, storage and disposal, are assigned to hazard classes.
    • Product Identifier discloses ingredient names or numbers used for a hazardous substance or mixtures.
    • Supplier identification should include the name, address and telephone number of the product supplier.
    • Supplemental information includes non-harmonized information that is not required or specified under GHS. Supplemental information may be used to provide additional detail about a product provided it does not contradict or create doubt regarding the validity of GHS standardized elements.

    GHS does not specify the actual label formatting and layout of the GHS elements. However, GHS does specify harmonized symbols, signal words and hazard statements, which should be located together on the label. GHS pictograms are expected to be proportional in relation to text size so GHS labels are different in appearance from Transport pictograms.

    GHS Safety Data Sheets

    GHS Safety Data Sheets (SDS) are also known in some existing systems as “Material Safety Data Sheets (MSDS). SDS provide comprehensive information about the chemical product, its hazards, and any protective measures. The GHS Safety Data Sheets contain 16 sections in a particular order. They include: Identification; Hazard identification; Composition/ information on ingredients; First-aid measures; Fire-fighting measures; Accidental release measures; Handling and storage; Exposure control/ personal protection; Physical and chemical properties; Stability and reactivity; Toxicological information; Ecological information; Disposal considerations; Transport information; Regulatory information; and Other information.