Globally Harmonized System (GHS)
The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is a voluntary international system that was developed by the United Nations for standardizing and harmonizing the classification and labeling of chemicals globally.
The Globally Harmonized System is not a regulation by itself, but is incorporated in the OSHA Hazard Communication/Right to Know Standard (29 CFR 1910.1200 Subpart Z). All hazardous substances and mixtures must to be classified and labeled in accordance with the new HazCom Standard from 1 June 2015.
The GHS is an international approach to hazard communication that:
- Defines physical, health and environmental hazards of chemicals and harmonizes classification criteria;
- Standardizes labeling requirements for chemical containers and Safety Data Sheets (formally known as Material Safety Data Sheets).
The GHS improves the safety of employees by providing more efficient and effective chemical hazard information. The standardization of chemical hazard information around the world ensures all pertinent knowledge is included on the labels and Safety Data Sheets (SDS). This system will enable faculty, staff, students, health professionals, and emergency respondents to access the most current data on chemical hazards they are in contact.
GHS Hazard Class, Hazard Category, Signal Word, and Pictograms
The GHS describes the nature and severity of a chemical hazard using the following:
- GHS hazard class – means the nature of the physical, health or environmental hazard, e.g. flammable solid, carcinogen, oral acute toxicity;
- GHS hazard category – means the division of criteria within each hazard class, e.g. oral acute toxicity includes 5 hazard categories and flammable liquids includes 4 hazard categories. The categories compare hazard severity within a hazard class and should not be taken as a comparison of hazard categories more generally;
- Signal word – means a word used to indicate the relative level of severity of hazard and alert the reader to a potential hazard on the label. The GHS uses “Danger” (more severe hazard) and “Warning” (less severe hazard) as signal words;
- Hazard pictogram – 9 pictograms are used to convey different types of health, physical and environmental hazards;
Hazard Classes
There are 29 GHS hazard classes in total. They are used to describe 3 main types of chemical hazards: physical hazards, health hazards and environmental hazards.
| Physical Hazards (17 classes) | Explosives
Flammable Gases
Aerosols
Oxidizing Gases
Gases Under Pressure
Flammable Liquids
Flammable Solids
Self-Reactive Substances
Pyrophoric Liquids
Pyrophoric Solids
Self-Heating Substance
Substances which, in contact with water emit flammable gases
Oxidizing Liquids
Oxidizing Solids
Organic Peroxides
Corrosive to Metals
Desensitized explosives |
| Health Hazards (10 classes) | Acute Toxicity (Oral/Dermal/Inhalation)
Skin Corrosion/Irritation
Serious Eye Damage/Eye Irritation
Respiratory or Skin Sensitization
Germ Cell Mutagenicity
Carcinogenicity
Reproductive Toxicology
Specific Target Organ Systemic Toxicity - Single Exposure
Specific Target Organ Systemic Toxicity - Repeated Exposure
Aspiration Toxicity |
| Environmental Hazards (2 classes) | Hazardous to Aquatic Environment (Acute/Chronic)
Hazardous to the Ozone Layer |
GHS Hazard Statement and Hazard Codes
Hazard statements are statements assigned to a hazard class and category that describe the nature of the hazard(s) of a chemical, including, where appropriate, the degree of hazard. According to the GHS, hazard statements will appear on both a chemical’s labeling and the Safety Data Sheet (SDS, Section 2. Hazard Identification).
There are 72 individual and 17 combined hazard statements each assigned a unique alphanumerical code consisting of one letter and three numbers according to the following system:
- The letter “H,” standing for “hazard statement”
- A number designating the type of hazard as follows
- Physical hazards – “2”
- Health hazards – “3”
- Environmental hazards – “4”
GHS Precautionary Statement and Precautionary Codes
Precautionary statements are phrases that describe recommended measures that should be taken to minimize or prevent adverse effects resulting from exposure to a hazardous chemical or improper storage or handling. According to the GHS, precautionary statements appear on both a chemical’s labeling and the Safety Data Sheet (SDS, Section 2. Hazard Identification).
There are 116 individual and 33 combined precautionary statements each assigned a unique alphanumerical code consisting of one letter and three numbers according to the following system:
