Ask the Expert, Chemicals, EHS Management, Emergency Preparedness and Response, Q&A

Identifying EHSs

Q. How do I identify extremely hazardous substances (EHSs) and hazardous substances on EPA’s List of Lists and SDSs?

A. Extremely hazardous substances (EHSs) are identified in 40 CFR 355 Appendices A & B. On EPA’s List of Lists, EHSs are identified under the column titled “Section 302 (EHS) TPQ.” On the SDS, you would refer to Section 3: Composition/Information on Ingredients to determine if the product contains an EHS.

Hazardous substances or hazardous chemicals are more difficult to identify because there is no list of such chemicals. Therefore, the determination of whether a chemical is hazardous must be made after evaluating OSHA’s definition and identifying pertinent information in Section 2: Hazard(s) Identification and Section 3: Composition/Information on Ingredients of the SDS.

Under 29 CFR 1910.1200(c), a hazardous chemical is defined as “any chemical which is classified as a physical hazard or a health hazard, a simple asphyxiant, combustible dust, pyrophoric gas, or hazard not otherwise classified.”

OSHA further defines some of the aforementioned terms as follows:

  • “Health hazard” means a chemical which is classified as posing one of the following hazardous effects: acute toxicity (any route of exposure); skin corrosion or irritation; serious eye damage or eye irritation; respiratory or skin sensitization; germ cell mutagenicity; carcinogenicity; reproductive toxicity; specific target organ toxicity (single or repeated exposure); or aspiration hazard. The criteria for determining whether a chemical is classified as a health hazard are detailed in Appendix A to §1910.1200–Health Hazard Criteria.
  • “Physical hazard” means a chemical that is classified as posing one of the following hazardous effects: explosive; flammable (gases, aerosols, liquids, or solids); oxidizer (liquid, solid or gas); self-reactive; pyrophoric (liquid or solid); self-heating; organic peroxide; corrosive to metal; gas under pressure; or in contact with water emits flammable gas. See Appendix B to §1910.1200-Physical Hazard Criteria.
  • “Simple asphyxiant” means a substance or mixture that displaces oxygen in the ambient atmosphere, and can thus cause oxygen deprivation in those who are exposed, leading to unconsciousness and death.
  • “Pyrophoric gas” means a chemical in a gaseous state that will ignite spontaneously in air at a temperature of 130 degrees F (54.4 degrees C) or below.