The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is a system for standardizing and harmonizing the classification and labeling of chemicals created by the United Nations.

GHS defines and classifies the hazards of chemical products and communicates health and safety information on labels and safety data sheets (SDS; commonly known as material safety data sheets [MSDS] in previous systems). It was designed to replace the various classification and labeling standards used in different countries with a consistent criteria for classification and labeling on a global level.

Health Hazardsspecified under GHS include the following classes:GHS Icon - Irritant

  • Acute toxicity
  • Skin corrosion
  • Skin irritation
  • Serious eye damage
  • Eye irritation
  • Respiratory sensitizer
  • Skin sensitizer
  • Germ cell mutagenicity
  • Carcinogenicity
  • Reproductive toxicity
  • Specific target organ toxicity (STOT)
  • Aspiration hazard

Physical Hazards specified under GHS include the following classes:

  • ExplosivesGHS - Physical Hazard Icaon
  • Flammable gases
  • Flammable aerosols
  • Oxidizing gases
  • Gases under pressure
  • Flammable liquids
  • Flammable solids
  • Self-reactive substances
  • Pyrophoric liquids
  • Pyrophoric solids
  • Self-heating substances
  • Substances which, on contact with water, emit flammable gases
  • Oxidizing liquids
  • Oxidizing solids
  • Organic peroxides
  • Substances corrosive to metal

Environmental Hazardsspecified under GHS include the following classes:

  • Acute aquatic toxicity
  • Chronic aquatic toxicity
Health Hazard Symbols
GHS Icon - Carcinogen GHS - Irritants GHS Icon - Acute Toxicity

Carcinogens, Respiratory Sensitizer, Target Organ Toxicity, Aspiration Toxicity, Reproductive Toxicity, Mutangenicity

Irritants, Dermal Sensitizers, Acute (Harmful) Toxicity, Narcotics, Respiratory Tract Irritation

Acute (Severe) Toxicity







Physical Hazard Symbols
GHS Icon - Oxidizers GHS Icon - Explosives GHS Icon - Flammable


Explosives, Organic Peroxides, Self Reactives

Flammables, Self Reactives, Pyrophorics, Emits Flammable Gas, Organic Peroxides, Self-Heating












Environmental Hazard Symbols
GHS Icon - Aquatic Toxicity    

Aquatic Toxicity














Hazard Communication & Labeling

Once a chemical has been classified, the hazard or hazards it presents must be communicated. Much like other systems, labels and SDSs are the main tools for chemical hazard communication in GHS. These tools are intended to identify the intrinsic hazards found in chemicals and chemical mixtures, and to convey information about those hazards.

GHS attempts to standardize hazard communication so that the intended audience can better understand the potential hazards of the chemicals at hand. It has established numerous guiding principles regarding hazard communication, including, but not limited to:

  • Hazard communication should be available in more than one form (i.e. placards, labels, or SDSs)
  • Hazard communication should include hazard statements and precautionary statements
  • Hazard communication information should be standardized and easy to understand
  • Hazard communication phrases should be consistent with each other to reduce confusion
  • Hazard communication should take into account all existing research as well as new evidence

Comprehensibility across multiple languages and cultures is a considerable challenge of GHS. Numerous factors were considered in developing the system’s communication tools, including the ability to translate phrases meaningfully and the ability to understand and appropriately respond to symbols/pictograms used in labeling.

Chemical labels under GHS must contain the following standardized elements:

  • Symbols/Pictograms conveying hazard information based on the chemical’s hazard class and category. Pictograms include the harmonized hazard symbol and other graphic elements such as borders and background patterns. A black symbol on a white background with a red diamond frame is the GHS standard for pictograms.
  • Signal Wordsemphasizing hazards and their relative level of severity. “Danger” is used for more severe hazards; “Warning” is used for less severe hazards; certain lower level hazard categories do not require signal words.
  • Hazard Statementsdescribing the nature of the hazard. GHS utilizes standard phrases that are assigned to each hazard class and category. Products presenting more than one hazard must include appropriate statements for each.

Additional GHS chemical label elements include precautionary statements, product identifiers (ingredient disclosures), supplier identification, and further supplemental information.

GHS specifies which signal words, pictograms, and hazard statements should be used for each hazard and class, and that all of these elements should be located together on the product label. Actual label format and layout is not specified by GHS; however, the size of pictograms in proportion to the size of text on labels is specified.

GHS Safety Data Sheets

GHS safety data sheets (SDS) are designed to provide comprehensive information about the chemical product, allowing employers and workers to obtain concise, relevant, and accurate information regarding the hazards, uses, and risk management of chemical products in the workplace. GHS safety data sheets must contain 16 sections, which must appear in the following specified order:

  1. Identification
  2. Hazard(s) identification
  3. Composition/information on ingredients
  4. First-aid measures
  5. Fire-fighting measures
  6. Accidental release measures
  7. Handling and storage
  8. Exposure control/personal protection
  9. Physical and chemical properties
  10. Stability and reactivity
  11. Toxicological information
  12. Ecological information
  13. Disposal considerations
  14. Transport information
  15. Regulatory information
  16. Other information


Training is key to the successful implementation of GHS, and new and updated information should be incorporated as it is introduced into the workplace. All employees and emergency responders must be trained on all new program elements. In the United States, all workers must be trained for GHS implementation by 1 December 2013.

A Brief History of GHS

Development of GHS began in 1992. That year, the International Labor Organization (ILO), the Organization for Economic Cooperation and Development (OECD), various governmental agencies, and other interested regulatory parties met at the United Nations’ Rio Conference.

Many countries represented by the above organizations and others already had regulatory systems in place which were similar in content and approach to GHS. However, their differences were significant enough to necessitate multiple classifications, labels, and SDS for the same product when marketed in different countries. Given the extent of international trade in chemicals, and the impact the production and use of chemicals has on national economies throughout the world, it was determined that a unified, worldwide approach to classification and labeling was necessary.

The Globally Harmonized System of Classification and Labeling of Chemicals was designed to replace these diverse, individual classification systems and act as a universal standard for all countries to follow (though its use is not mandatory under UN law). It provides the infrastructure for participating countries to implement a hazard classification and communication system, and is intended to improve knowledge of the health hazards chemicals can present, with an eye toward eliminating hazardous chemicals and/or replacing them with less dangerous substances.

Adoption of GHS is expected to facilitate international trade by providing consistency between the laws of different countries. Though there is no set implementation schedule for GHS, the UN had hoped for broad international adoption by 2008. In the United States, the final rule for implementation of GHS was published in March 2012, requiring manufacturers to implement GHS by 1 June 2015 and product distributors to adopt the standard by 1 December 2015.