Definition of Hazardous Chemicals
 The purpose of this section is to provide resources and information that can be used to evaluate the hazards of chemicals. The terms used in this section are listed in the glossary.
The OSHA Hazard Communication Standard defines a hazardous chemical as a chemical that is either a health hazard or a physical hazard.
Health Hazard
A "health hazard" is 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 that are carcinogens, toxic or highly toxic agents, reproductive toxins, irritants, corrosives, sensitizers, hepatotoxins (liver toxins), nephrotoxins (kidney toxins), neurotoxins, agents that act on the hematopoietic (blood-forming) system, and agents that damage the lungs, skin, eyes, or mucous membranes.
Physical Hazard
A chemical is a physical hazard if it has flammable, combustible, explosive, oxidizing, pyrophoric, or reactive (including water reactive) properties, or if it is an organic peroxide or compressed gas.
Information and Resources
The following sources of information may be used to determine the hazards of chemicals:
Material Safety Data Sheets. MSDSs list both health and physical hazards of chemicals.
Moreover, an EH&S Industrial Hygienist may also be consulted to assist in evaluating chemical hazards. 
Mixtures
Many products used in the workplace are mixtures of different chemicals. In accordance with OSHA, a mixture is assumed to present the same health hazards as each component that comprises 1% or more of the mixture. A mixture is assumed to be carcinogenic if it contains a carcinogenic component in a concentration of 0.1% or more.
The Chemical Toxicology Overview located in the appendices has additional information on the health effects of chemicals.
Particularly Hazardous Substances
OSHA established a category of chemicals known as particularly hazardous substances for which additional precautions beyond standard operating procedures may be required. Particularly hazardous substances include select carcinogens, reproductive toxins, and substances with a high degree of acute toxicity.
Work Leads are responsible for work involving particularly hazardous substances and to ensure that proper controls are in place and that area-specific training may be given. An EH&S Industrial Hygienist may be consulted to provide assistance. For some work, an Activity Hazard Document may be required. The section entitled Particularly Hazardous Substances provides additional information for the identification and control of these chemicals.
Engineered Nanomaterials
“Engineered” nanomaterials" are:
- Discrete materials having structures with at least one dimension between 1 and 100 nanometers (nm).
- Intentionally created, as opposed to those that are naturally or incidentally formed.
Engineered Nanomaterials do not include:
- Larger materials that may have nanoscale features, for example etched silicon wafers.
- Biomolecules (proteins, nucleic acids, and carbohydrates),
- Materials with occupational exposure limits (OELs) that address nanosized particles for that substance.
Nanoparticles are a type of engineered nanomaterials that:
- Are not bound to a surface or weakly bound to a surface and therefore are or may become dispersible
- Have two or three dimensions between 1 and 100 nm.
Exposures to these materials may occur through inhalation, dermal contact, and ingestion. Animal studies indicate that low-solubility ultra-fine particles may be more toxic than larger ones on a mass-for-mass basis. Because of their tiny size, they can penetrate deep into the lungs and may translocate to other organs following pathways that have not been demonstrated in studies with larger particles. In addition, the nanoparticulate forms of some materials show higher reactivity, especially for fire, explosion, and in catalytic reactions.
Consumables
Consumables are materials such as solder, welding rods and grinding wheels. These are considered as hazardous materials because they may produce airborne dust, fumes or particulates when used in the manner intended by the manufacture. Wood is also considered as a hazardous material if it is cut or sawn to produce airborne dust.
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Last updated: 08/31/2010 |
