CHEMICAL HAZARDS

Hazardous materials include chemicals, gases and cryogens.  This section defines different types of hazardous chemicals. Later sections describe hazard assessment and control to minimize personnel risk..

Definition of Hazardous Chemicals

The OSHA Laboratory Standard defines a hazardous chemical 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. 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.   LBNL expands this definition to also include chemicals that pose physical hazards.  A chemical is a physical hazard if it has flammable, combustible, explosive, oxidizing, pyrophoric, or reactive properties, or if it is an organic peroxide or compressed gas.

A chemical is considered hazardous if it is listed in any of the following:

• A Material Safety Data Sheet (i.e., if the MSDS identfies it as a chemical or physical hazard)
• OSHA 29 CFR 1910.1000 Table Z-l through Z-3
• Threshold Limit Values for Chemical Substances and Physical Agents in the Work Environment, American Conference of Governmental Industrial Hygienists (ACGIH), latest edition
• The Registry of Toxic Effects of Chemical Substances (RTECS), National Institute for Occupational Safety and Health NIOSH (latest edition).

An EH&S Industrial Hygienist may also declare a substance hazardous based upon professional judgment or a review of data. 

Manufacturers are required to determine the hazardous properties of the materials they produce. This information is conveyed through Material Safety Data Sheets and Labels.

The Chemical Toxicology Overview located in the appendices has additional information on the health effects of chemicals.

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. (A glossary of common terms is provided.)

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.

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