Appendix B - NFPA Label Information

                                             NFPA 704 Hazard Rating System

The National Fire Protection Association (NFPA 704) system uses an a diamond-shaped diagram of symbols and numbers to indicate the degree of hazard associated with a particular chemical or material. These diamond- shaped symbols are placed on containers of chemicals or materials to identify the degree of hazard associated with the chemical or material. 

The diagram identifies three color-coded categories of hazard for each material:

NFPA rating
  • health hazard (blue sections),

  • flammability (red sections),

  • reactivity (yellow sections), and  

  • other hazard information (white section).

Each category is divided in five levels of hazard potential with

  • zero (0) used to indicate no special hazards and
  • four (4) for severe or extreme hazard potential. 

The degrees of hazard in each of these categories are given as follows:

Health - The degree of health hazard of a chemical or material is based on the form or condition of the material, as well as its inherent properties  (NFPA ratings)..   The degree of health hazard of a material should indicate the degree of personal protective equipment required for working safety with the material:

  1. A rating of 1 is for slightly hazardous (toxic) material which require only minimal protection (for example, safety glasses and gloves) in addition to normal work clothing to work with safely
  2. A rating of 2 is for moderately toxic or hazardous material which require additional PPE or equipment (e.g. chemical goggles, lab/work smock, local ventilation) in addition to that required for less toxic material. Consult the MSDS for specific health hazard and proper PPE to use with this material.
  3. A rating of 3 or 4 is for highly to extremely toxic (deadly) material (and any carcinogen, mutagen, or teratogen).   These materials will require specialized equipment (e.g. respirator (or exhaust hood), full face shield, rubber apron, specialized glove, handling tongs, etc) beyond that required for moderately toxic material. You must consult the MSDS and/or other safety information to determine the hazard (acute or chronic) and the proper PPE and engineering controls to safely use of this material.

Flammability - The flammability hazards deal with the degree of susceptibility of the material to ignite and burn.  The form or condition of the materials, as well as their properties, affects the extent of the hazard.  Many hazardous materials such as acetone and gasoline, have a flash point (ignition temperature) far below freezing and will readily ignite with a spark if the vapor concentration is sufficient. A low rating of 1 is for material with a flash point above 200F while more hazardous ratings of 2, 3, and 4 are for materials with respective flash point below 200, 100 and 73 F. (NFPA ratings)

Reactivity - The reactivity hazards deal with the potential of a material or chemical to release energy.  Some materials are capable of rapid release of energy without any catalyst, while others can undergo violent eruptive or explosive reactions if they come in contact with water or other materials.  Generally this rating is used to indicate the potential to reactive if the material is heated, jarred, or shocked.. A low rating of 1 indicates a material that is normally stable but may be reactive if heated.  The more hazardous ratings of 2, 3, and 4 indicate a material is capable of violent reaction, shock/rapid heating and detonation respectively (NFPA ratings)

Other Hazard Information - An open space at the bottom of the NFPA diagram can be used to indicate additional information about the chemical or material.  This information may include the chemical or material's radioactivity, proper fire extinguishing agent, skin hazard, its use in pressurized containers, protective equipment required, or unusual reactivity with water.  For example, the usual signal to indicate unusual reactivity with water is the letter "W" with a long line through the center. Similarly the words ACID, COR (corrosive), RAD (radiation), OXY (oxidizer), Rad (radioactive), CARC (carcinogen) or other abbreviations may be used.

The following shows a summary of the NFPA rating system used for labeling secondary containers of chemicals. (Click the image for a screen size printable label)

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NFPA ratings for common chemicals 


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