As defined by OSHA Standard 1910.1200 (the OSHA Haz-com standard), a hazardous chemical is one which is a physical hazard or a health hazard. Health Hazard: Health hazard means 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. The term "health hazard" includes chemicals which are carcinogens, toxic or highly toxic agents, reproductive toxins, irritants, corrosives, sensitizers, hepatotoxins, nephrotoxins, neurotoxins, agents which act on the hematopoietic system, and agents which damage the lungs, skin, eyes, or mucous membranes. Appendix A provides further definitions and explanations of the scope of health hazards covered by this section, and Appendix B describes the criteria to be used to determine whether or not a chemical is to be considered hazardous for purposes of this standard. Physical Hazard: Physical hazard means a chemical for which there is scientifically valid evidence that it is a combustible liquid, a compressed gas, explosive, flammable, an organic peroxide, an oxidizer, pyrophoric, unstable (reactive) or water-reactive. Further Information Under the OSHA HazCom standard 1910.1200, "Chemical manufacturers and importers shall evaluate chemicals produced in their workplaces or imported by them to determine if they are hazardous. Employers are not required to evaluate chemicals unless they choose not to rely on the evaluation performed by the chemical manufacturer or importer for the chemical to satisfy this requirement. The following two sources establish chemicals as being hazardous: (1) 29 CFR part 1910, subpart Z, Toxic and Hazardous Substances, Occupational Safety and Health Administration (OSHA) or, (2) "Threshold Limit Values for Chemical Substances and Physical Agents in the Work Environment," American Conference of Governmental Industrial Hygienists (ACGIH) (latest edition). The chemical manufacturer, importer, or employer is still responsible for evaluating the hazards associated with the chemicals in these source lists in accordance with the requirements of this standard. Hazard vs Risk - A hazard is an inherent (built-in) property of a material. Risk is the extent to which that material can cause harm. You can reduce or remove risks associated with a hazardous material, but you can not remove the underlying hazard itself (unless you get rid of the hazardous material, of course). For example, gasoline is hazardous, but it does not have a significant risk provided that proper use and storage precautions have been taken. See: The last three links under Further Reading below for more information and discussion on this very fine (but very important) point. MSDS Relevance: Material safety data sheets provide the necessary information for you to understand and deal with the potential hazards associated with a particular substance. Read the sheet carefully before you use a hazardous material for the first time or any time you are unsure about the hazards or necessary precautions. The MSDS can help you reduce the risks (but not the underlying hazards; See: Above) associated with the materials in your workplace. Remember: MSDS's are only required for materials that are hazardous. Often times, manufacturers are asked for MSDS's for products that do not meet this requirement - manufacturers are under no obligation to produce MSDS's for non-hazardous materials. Both we and OSHA discourage the production of MSDS's for non-hazardous materials (listen up, corporate attorneys). Our MSDS FAQ contains more information and a list of materials that may not require MSDS's under the OSHA HazCom Standard. See also: Toxic, Carcinogen.