Environmental, Health and Safety Services

NFPA Labeling System

This system was developed by NFPA in the 1950's and the label is divided into sections (diamond or rectangle with bars), each color-coded and numbered 0 through 4 to have specific meanings.

NFPA Diagram

  • Health (blue)
    • 0 - Non-toxic (although no chemical is without some toxicity)
    • 1 - Slightly toxic: may cause irritation, but only minor residual injury even without treatment. Recognized innocuous materials when used with responsible care.
    • 2 - Moderately toxic: intense or continued exposure could cause temporary incapacitation or possible residual injury unless prompt medical treatment is given.
    • 3 - Serious toxic: short-term exposure could cause serious temporary or residual injury even though prompt medical treatment is given. Includes known or suspect small animal carcinogens, mutagens, or teratogens.
    • 4 - Highly toxic: very limited exposure could cause death or major injury even though prompt medical treatment is given. Includes known or suspect human carcinogens, mutagens, or teratogens.
  • Fire (red)
    • 0 - Non-combustible: materials which will not burn.
    • 1 - Slightly combustible: materials which require considerable preheating before ignition can occur. This rating includes most ordinary combustible materials, such as wood, paper, plastic.
    • 2 - Combustible: materials which must be moderately heated before ignition can occur. Including liquids having a flash point above 100° F, and solids which readily give off flammable vapors.
    • 3 - Flammable: liquids and solids that can be ignited under almost all ambient temperature conditions. Including liquids with a flash point below 73° F and a boiling point above 100° F, solid materials which form coarse dusts that burn rapidly without becoming explosive, materials which burn rapidly by reason of self-contained oxygen (i.e. organic peroxides), and materials which ignite spontaneously when exposed to air (pyrophorics).
    • 4 - Extremely flammable: materials which will rapidly vaporize at normal pressure and temperature, and will burn readily. Including gases, cryogenic materials, any liquid or gaseous material having a flash point below 73° F and a boiling point below 100° F, and materials which can form explosive mixtures with air.
  • Reactivity (yellow)
    • 0 - Stable: (even under fire conditions) and not reactive with water.
    • 1 - Normally stable: but which can become unstable at elevated temperature and pressures, or which may react with water with some release of energy, but not violently.
    • 2 - Normally unstable: readily undergo violent chemical change, but do not detonate. Including materials which may react violently with water or which may form potentially explosive mixtures with water.
    • 3 - Capable of detonation: but which require a strong initiating source, or which must be heated first. This rating includes materials which are shock-sensitive at elevated temperatures, and which react explosively with water without requiring heat.
    • 4 - Readily capable of detonation or explosive decomposition at normal temperatures and pressures: Includes materials which are shock-sensitive at normal temperatures and pressures.
  • Special notice or protective equipment (white)
    • "OX" - Denotes material is considered an oxidizing agent. These compounds give up oxygen easily, remove hydrogen from other compounds, or attract negative electrons.
    • "W" - Denotes material is considered water reactive. These compounds undergo rapid energy releases on contact with water. Use no water.
    • "ACID" - Denotes material is considered an acid.
    • "ALK" - Denotes material is considered an alkali
    • "COR" - Denotes material is considered a corrosive.
    • Radioactive symbol may also be found here. Denotes material is considered to be radioactive.
    • Protective equipment, such as safety glasses, goggles, gloves, etc. would be specified here.