Pictogram 2: Flame Over Circle - Oxidizers

The HCS definition of an "oxidizer" is a "chemical other than a blasting agent or explosive as defined in (29 CFR] 1910.109[a]), that initiates or promotes combustion in other materials, thereby causing fire either of itself or through the release of oxygen or other gases."

Put into more simple terms, an oxidizing agent is either a chemical or a substance that causes an oxidation reaction. An oxidation reaction is any reaction that involves the moving of electrons: fire, the browning of fruit, rusting of metals, and even plant photosynthesis are all examples of basic life functions where an oxidation reaction occurs.

An oxidizer can already contain oxygen or it can receive electrons during the reaction from another substance that is undergoing oxidation. For example, chlorine contains no oxygen, but it is an oxidizing agent that promotes electron transfers.

Oxidizers can either initiate the burning of a fuel or accelerate its burning. Oxygen from the atmosphere is the most common oxidizer, but chemicals that contain oxygen (like hydrogen peroxide or nitrous oxide) and halogens (such as bromine, chlorine, and fluorine) are also oxidizers. Some oxidizers have such a high potential of causing fire that they are not classified as oxidizers but rather as explosives.

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