NFPA Chemical Hazard Label

The National Fire Protection Association (NFPA) has developed a color coded, numerical system for indicating the health, flammability and reactivity hazards of chemicals. In addition, a special precaution symbol may be used if necessary.

NFPA labels are required on all chemicals in the laboratory. Some chemicals that we purchase already have these markings (or their equivalents) on the container. Other ones don't have such markings and should have a NFPA label put on them immediately.

To assist you in assessing the degree and type of hazard associated with a particular substance, we have provided these guidelines for you to follow.

Degree of Hazards

Each of the three colored areas in the NFPA fire diamond has a box in which the degree of hazard can be written. The degree of hazard is given by these numbers:

Number Degree of Hazard
4 EXTREME
3 SERIOUS
2 MODERATE
1 SLIGHT
0 MINIMAL

Types of Hazards

The diamond is subdivided into four general categories:

  1. Health (blue)
  2. Flammability (red)
  3. Reactivity (yellow)
  4. Special (white)

For each class of materials, here are guidelines and examples to help you assign or understand a hazard rating:

HEALTH
4 Extreme Highly toxic material. Will have one or more of the following characteristics:
  • On very short exposure could cause death or major residual injury even though prompt medical treatment is given.
    		•
  • A known or suspected human carcinogen, mutagen or teratogen.
    		•
    3 Serious Toxic material. Will have one or more of the following characteristics:
  • May cause serious temporary or residual injury on short term exposure even though prompt medical attention is given.
    		•
  • A known or suspected small animal carcinogen, mutagen or teratogen.
    		•
    2 Moderate Moderately toxic material. Will have one or both of the following characteristics:
  • Intense or continued exposure could cause temporary incapacitation or possible residual injury unless prompt medical treatment is given.
    		•
    1 Slight Slightly toxic material. Will have one or more of the following characteristics:
  • May cause irritation but only minor residual injury even without treatment.
    		•
  • Recognized innocuous material when used with responsible care.
    		•
    0 Minimal No chemical is without some degree of toxicity.

    FLAMMABILITY
    4 Extreme Extremely flammable. Flash point below 73 F (22.8 C)
    3 Serious Flammable. Will have one or more of the following characteristics:
  • Vaporizes readily and can be ignited under almost all ambient conditions.
    		•
  • May form explosive mixtures with or burn rapidly in air.
    		•
  • May burn rapidly due to self-contained oxygen.
    		•
  • May ignite spontaneously in air
    		•
  • Flash point at or above 73 F (22.8 C) but less than 100 F (37.8 C).
    		•
    2 Moderate Combustible. Will have one or more of the following characteristics:
  • Must be moderately heated or exposed to relatively high temperatures for ignition to occur.
    		•
  • Solids which readily give off flammable vapors.
    		•
  • Flash point at or above 100 F (37.8 C) but less than 200 F (93.4 C).
    		•
    1 Slight Slightly combustible. Will have one or more of the following characteristics:
  • Must be preheated for ignition to occur.
    		•
  • Will burn in air when exposed at 1500 F (815.5 C) for 5 minutes.
    		•
  • Flash point at or above 200 F (93.4 C).
    		•
    0 Minimal Will have one or more of the following characteristics
  • Will not burn
    		•
  • Will not exhibit a flash point
    		•
  • Will not burn in air when exposed at 1500 F (815.5 C) for 5 minutes.
    		•

    REACTIVITY
    4 Extreme Will have one or more of the following characteristics
  • Can explode or decompose violently at normal temperature and pressure.
    		•
  • Can undergo a violent self-accelerating exothermic reaction with common materials or by itself
    		•
  • May be sensitive to mechanical or local thermal shock at normal temperature and pressure.
    		•
    3 Serious Will have one or more of the following characteristics:
  • Can detonate or explode but requires a strong initiating force or confined heating before initiation
    		•
  • Readily promotes oxidation with combustible materials and may cause fires
    		•
  • Is sensitive to thermal or mechanical shock at elevated temperatures.
    		•
  • May react explosively with water without requiring heat or confinement.
    		•
    2 Moderate Will have one or more of the following characteristics:
  • Normally unstable and readily undergoes violent change but does not detonate.
    		•
  • May undergo chemical change with rapid release of energy at normal temperature and pressure.
    		•
  • May react violently with water.
    		•
  • Forms potentially explosive mixtures with water
    		•
    1 Slight Will have one or more of the following characteristics:
  • Normally stable material which can become unstable at high temperature and pressure.
    		•
    0 Minimal Normally stable material which is not reactive with water

    SPECIAL
    Water Reactive
    Ox Oxidizing Agent
    Radioactive
    Poison

    You can find hazard ratings for common laboratory chemicals at Michigan State University.

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