By Little Pro on 2016-01-06 Views: Update:2017-01-18
GHS describes the nature and severity of a chemical hazard by hazard class and hazard category:
There are 29 GHS hazard classes in total in UN GHS Rev. 6. They are used to describe 3 main types of chemical hazards: physical hazards, health hazards and environmental hazards.
|Physical Hazards(17 classes)||
|Health Hazards(10 classes)||
|Environmental Hazards(2 classes)||
GHS has provided standard chemical classification criteria which are used to determine the hazard class and hazard category of a chemical. The picture below is an example of GHS classification criteria for flammable liquids. A liquid with a flash point between 23 and 60 Celsius degrees will be classified as flammable liquid category 3. A liquid with a flash point above 93 Celsius degrees does not meet GHS classification criteria and will not be regarded as a hazardous chemical.
Standard hazard pictograms, hazard statements and precautionary statements will be assigned once the hazard class and hazard category of a chemical has been determined. (see example below).
GHS allows individual countries or regions to choose which hazard classes or hazard categories to implement to meet their domestic needs. For example, EU has not adopted flammable liquids category 4. The United States has not adopted Hazardous to the Ozone Layer yet. This is often called GHS Building Block approach.