GHS is an acronym for General Harmonized System for the Classification and Labeling of chemicals. The system is an initiative aimed at communicating the potential risk that various chemical poses to health and the environment. It makes use of standardized pictograms that visually reflect the nature of the risk to persons who get directly or indirectly exposed to the chemicals.

To make it possible to use a limited set of ghs pictograms for a wide range of chemicals, the chemicals are placed in clearly defined classes. The classes contain chemical substances that pose similar risks to health and the environment. By assigning a single pictogram to a class of chemicals, it thus becomes easier for an individual to immediately identify the hazard involved from just a single glance of the ghs pictogram.

There are three broad categories where these workplace hazard warnings can be placed. These three categories are physical hazard pictograms, health hazard pictograms and environmental hazard pictograms. Below are descriptions of some common ghs pictograms found in the workplace.

a) Explosive
This pictogram is composed of a four-sided diamond shape defined by a red band. At the center of the enclosed white background is a black sphere with rays and shards radiating from its center. This pictogram indicates that a substance is highly unstable and can spontaneously produce an explosive force having the potential of causing physical injury through the resulting shrapnel.

b) Highly flammable
As with the explosive pictogram, the highly flammable pictogram also a four-sided diamond shape defined by a red band. At the center of the white background within, is a fire hovering over a short black bar. This pictogram is used on chemicals that can easily ignite to produce fire when exposed to temperatures higher than 60 degrees Celsius. The chemical, therefore, has the potential of causing physical burns due to the ensuing fire.

c) Oxidizing Agent
This pictogram also bears a four-sided diamond defined by a red band. In the white background within, is the outline of an orb floating over a short black bar. The final detail on the orb are tongues of fires on its upper half. This pictogram is used to indicate a chemical substance that supports combustion by releasing oxygen. The chemical itself is usually not flammable. The chemical, therefore, poses the potential of perpetuating a fire that would result in physical burns.

d) Corrosive
This pictogram also features a four-sided diamond defined by a red band. Within the enclosed white background is a diagonally inclined glass test tube with a liquid dripping onto a short black bar. The bar is sometimes replaced by an open hand with all five fingers visible. In either case, one is bound to note that the liquid dripping from the test tube appears to be eating into the bar or hand. This pictogram is used on chemicals that can cause chemical burns by eating away the exposed skin.

A government regulation, the Hazard Communication Standard, requires the use of ghs pictograms on warning labels for chemicals used in the workplace. The regulation also makes the pictograms a prerequisite when transporting dangerous goods. A company or other legal entity must, therefore, abide by the HCS regulation for it to be ghs compliant.