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OSHA defines a hazardous chemical as any chemical which is a physical hazard or a health hazard. OSHA further defines a health hazard as a chemical for which there is statistically significant evidence based on at least one study conducted in accordance with established scientific principles that acute or chronic health effects may occur in exposed employees. This includes chemicals which are carcinogens, toxic or highly toxic agents, reproductive toxins, irritants, corrosives, sensitizers, hepatoxins, nephrotoxins, neurotoxins, agents which act on the hematopoietic system, and agents which damage the lungs, skin, eyes, or mucous membranes. This also includes chemicals in all physical forms — liquids, solids, gases, vapors, fumes, and mists — whether they are “contained” or not.
The hazardous nature of the chemical and the potential for exposure are the factors which determine whether a chemical is covered under the HazCom standard. If it’s not hazardous, it’s not covered. If there is no potential for exposure (e.g., the chemical is inextricably bound and cannot be released), the rule does not cover the chemical.