National Fire Protection Association Hazard Identification System

The National Fire Protection Association (NFPA) has a system for indicating the health, flammability, and reactivity hazards of chemicals. You may see this diamond shaped label on some material safety data sheets and product labels.
0 = Minimum Hazard
4 = Extreme Hazard


    0. No unusual hazard
    1. CAUTION! May be irritating.
    2. WARNING! May be harmful if inhaled or absorbed.
    3. WARNING! Corrosive or toxic. Avoid skin contact or inhalation.
    4. DANGER! May be fatal on short exposure. Protective equipment required.
    0. Not combustible.
    1. Only slightly flammable. Must be preheated to burn
    2. CAUTION! Flammable if moderately heated. Flash point of 100 to 200 degrees F.
    3. WARNING! Flammable under normal temperature conditions. Flash point below 100 degrees F.
    4. DANGER! Very flammable gases or very volatile flammable liquids
    0. STABLE. Not reactive when mixed with water.
    1. CAUTION! May react if heated or mixed with water, but not violently.
    2. WARNING! Unstable or may react violently if mixed with water.
    3. DANGER! May be explosive if shocked, heated under confinement, or mixed with water.
    4. DANGER! Readily capable of detonation or explosive decomposition at normal temperatures.
Additional Markings -- this white space is used to place special codes to further identify hazards.

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