If you work with chemicals in any capacity — manufacturing, shipping, laboratory, healthcare, or even custodial work — you've seen those distinctive red-bordered diamond symbols on containers. Those are GHS hazard pictograms, and they're part of a worldwide system designed to keep you safe.
GHS stands for the Globally Harmonized System of Classification and Labelling of Chemicals. It was developed by the United Nations and first published in 2003, with the goal of creating a single, universal approach to chemical hazard communication.
Before GHS, different countries used completely different systems. A chemical might be labeled "toxic" in one country and merely "harmful" in another, using different symbols and different safety data formats. This was dangerous for international trade and for workers.
GHS has three main components that work together. First, classification criteria: standardized tests and thresholds that determine what category of hazard a chemical falls into. Second, label elements: the pictograms, signal words, hazard statements, and precautionary statements that go on every container. Third, Safety Data Sheets (SDS): the standardized 16-section document that provides detailed safety information.
There are exactly nine pictograms in the GHS system. Each is a red diamond with a white background and a black symbol. They cover explosive, flammable, oxidizing, compressed gas, corrosive, acutely toxic, irritant/harmful, serious health hazard, and environmental hazards. You can learn about each one in detail on our symbols reference pages.
In the US, GHS is implemented through OSHA's Hazard Communication Standard (HCS 2012), codified at 29 CFR 1910.1200. It became fully effective on June 1, 2015, and was updated in 2024 to align with GHS Revision 7. All chemical manufacturers, importers, distributors, and employers must comply.
GHS isn't just regulatory paperwork — it's a communication system designed to save lives. Understanding the pictograms, reading the labels, and knowing where to find the SDS are fundamental safety skills for anyone who works with chemicals.