GHS Pictogram Review: Oxidizers

Chemicals with oxidizing properties are identified by the Flame Over Circle Pictogram.  The “O” represents oxygen and the flames indicate that the substance is a hazardous oxidizer that can cause a fire or explosion if not handled properly.  This pictogram is used for oxidizing solids, liquids, or gases. Oxidizers are not necessarily combustible on their own, but they can intensify combustion and increase the flammable range for chemicals helping them to ignite more readily. Fires involving oxidizers will burn hotter and longer.

Older containers of oxidizers can also be recognized by yellow color coding on the label as in the example shown at right.  It is important to be able to identify oxidizers based on their chemical name or by referencing the Safety Data Sheet.

How to safely handle and store oxidizers:

• Store oxidizers away from other chemicals and away from potential heat sources.  You should have a separate storage location away from your general chemical storage area, which likely holds organic chemicals and/or reducing agents that can react violently with oxidizers.
• When a lab procedure requires mixing of a strong oxidizer with an organic chemical, seek more specific information on the reactivity of the particular chemicals. The mixing can result in a violent reaction.
• Use oxidizers in a chemical fume hood. If there is a risk of explosion or violent reaction, you should use the hood sash as a protective barrier between you and the hazard.
• Always wear appropriate personal protective equipment.
• Observe appropriate chemical handling practices, like never returning a chemical to its original container.

If you’re unconvinced about the importance of segregating oxidizers from your general chemical storage, check out this video of the reaction between potassium chlorate (an oxidizer) and sugar (an organic compound) and imagine what could happen if there were a fire in your lab and you stored your oxidizers in the same cabinet as organics: