Hazard pictograms form part of the international Globally Harmonized System of Classification and Labelling of Chemicals (GHS). Two sets of pictograms are included within the GHS: one for the labelling of containers and for workplace hazard warnings, and a second for use during the transport of dangerous goods. Either one or the other is chosen, depending on the target audience, but the two are not used together. The two sets of pictograms use the same symbols for the same hazards, although certain symbols are not required for transport pictograms. Transport pictograms come in wider variety of colors and may contain additional information such as a subcategory number.
Hazard pictograms are one of the key elements for the labelling of containers under the GHS, along with:
an identification of the product;
a signal word – either Danger or Warning – where necessary
hazard statements, indicating the nature and degree of the risks posed by the product
precautionary statements, indicating how the product should be handled to minimize risks to the user (as well as to other people and the general environment)
the identity of the supplier (who might be a manufacturer or importer)
The GHS chemical hazard pictograms are intended to provide the basis for or to replace national systems of hazard pictograms. It has still be implemented by the European Union (CLP regulation) in 2009.
Gases which at 20 °C and a standard pressure of 101.3 kPa:
are ignitable when in a mixture of 13 per cent or less by volume with air; or
have a flammable range with air of at least 12 percentage points regardless of the lower flammable limit.
Non-flammable non-toxic gases
are asphyxiant – gases which dilute or replace the oxygen normally in the atmosphere; or
are oxidizing – gases which may, generally by providing oxygen, cause or contribute to the combustion of other material more than air does; or
do not come under the other divisions;
are known to be so toxic or corrosive to humans as to pose a hazard to health; or
are presumed to be toxic or corrosive to humans because they have an LC50 value equal to or less than 5000 ml/m3 (ppm).
Classes 3 and 4: Flammable liquids and solids
Liquids which have a flash point of less than 60 °C and which are capable of sustaining combustion
Flammable solids, self-reactive substances and solid desensitized explosives
Solids which, under conditions encountered in transport, are readily combustible or may cause or contribute to fire through friction; self-reactive substances which are liable to undergo a strongly exothermic reaction; solid desensitized explosives which may explode if not diluted sufficiently
Substances liable to spontaneous combustion
Substances which are liable to spontaneous heating under normal conditions encountered in transport, or to heating up in contact with air, and being then liable to catch fire
Substances which in contact with water emit flammable gases
Substances which, by interaction with water, are liable to become spontaneously flammable or to give off flammable gases in dangerous quantities