NFPA Chemical Hazard Codes



The National Fire Protection Association (NFPA) is a professional firefighters organization that works to prevent the loss of life and property from fire. NFPA has developed regulations, guideline, and procedures to prevent fires, protect individuals during fires, reduce losses due to fires, and how to respond to emergency situations. NFPA has developed a standard system, called the NFPA chemical hazard codes, for classifying the health, flammability, and reactivity hazards of chemicals during an emergency situation. A standard label called the NFPA chemical hazard label has also been developed to be used by chemical manufacturers.

This system of identifying hazards associated with various chemicals was developed primarily for fire protection and emergency personnel. As stated in NFPA Code #704, “This standard provides a simple system of readily recognizable and easily understood markings, which will give, at a glance, a general idea of the inherent hazards of any materials and the order of severity of these hazards as they relate to fire prevention, exposure and control.” The NFPA chemical hazard codes and label are not intended as a guide for workplace exposure or for relative indices of toxicity.

The NFPA chemical hazard label is a multicolored, 4-part diamond as shown in Figure 1. The four parts of the diamond are each color-coded and represent a particular hazard—health (blue), flammability (red) and reactivity (yellow). The bottom part of the diamond is left blank for special hazards such as water-reactive materials or strong oxidizers. The NPFA hazard code uses a 0–4 rating system where 0 is no unusual hazard and 4 is danger. A more specific explanation for each hazard is outlined in the Discussion section.

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General NFPA Rating Summary

Health (Blue)

4 Danger May be fatal on short exposure. Specialized protective equipment required.
3 Warning Corrosive or toxic. Avoid skin contact or inhalation.
2 Warning May be harmful if inhaled or absorbed.
1 Caution May be irritating.
0 No unusual hazard.

Flammability (Red)

4 Danger Flammable gas or extremely flammable liquid.
3 Warning Flammable liquid flash point below 100 °F.
2 Caution Combustible liquid flash point of 100 ° to 200 °F.
1 Combustible if heated.
0 Not combustible.

Reactivity (Yellow)

4 Danger Explosive material at room temperature.
3 Danger May be explosive if shocked, heated under confinement or mixed with water.
2 Warning May undergo violent chemical change at elevated temperatures or pressures.
1 Caution Normally stable but the material may be unstable at elevated temperatures or pressures.
0 Stable Materials that are normally stable, even under fire conditions.

Special Notice Key (White)

W Water Reactive
OX Oxidizing Agent

NFPA chemical hazard codes are found on many labels and are sometimes required on storage room doors. The NFPA hazard codes and the NFPA chemical hazard label are used by firefighters to warn them of hazards during an emergency situation. They are not intended as a guide for workplace exposure or for relative toxicity levels. Flinn At-A-Glance codes, HMIS codes or Safety Data Sheets (SDSs) are better suited as guides for workplace and classroom hazards.

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