What Do GHS Pictograms Mean?

GHS pictograms are the hazard symbols on chemical labels. OSHA's Hazard Communication standard defines a pictogram as a symbol plus other graphic elements, such as a border, background pattern or color, intended to convey specific information about a chemical's hazards, and requires each one to be a square set on its point with a black hazard symbol on a white background inside a red frame. OSHA says the GHS uses nine pictograms but OSHA enforces only eight, because the environment pictogram is not mandatory, though label preparers may add it as supplementary information.

OSHA's pictogram QuickCard pairs each symbol with the hazards it covers. The health hazard symbol marks carcinogens, mutagenicity, reproductive toxicity, respiratory sensitizers, target organ toxicity and aspiration toxicity. The flame marks flammables, pyrophorics, self-heating materials, chemicals that emit flammable gas, self-reactives, organic peroxides and desensitized explosives. The exclamation mark marks skin and eye irritants, skin sensitizers, harmful acute toxicity, narcotic effects and respiratory tract irritants.

The gas cylinder marks gases under pressure. The corrosion symbol marks skin corrosion or burns, eye damage and chemicals corrosive to metals. The exploding bomb marks explosives, self-reactives and organic peroxides, and the flame over circle marks oxidizers. The skull and crossbones marks acute toxicity that is fatal or toxic, and the non-mandatory environment symbol marks aquatic toxicity.

Labels also carry a signal word. OSHA says only two are used, Danger for the more severe hazards within a hazard class and Warning for the less severe ones, and that a label carries only one signal word no matter how many hazards a chemical has, so if any hazard warrants Danger, only Danger appears.