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NFPA - National Fire Protection Association


The National Fire Protection Association, NFPA, a private non-profit organization, is the leading authoritative source of technical background, data, and consumer advice on fire protection, problems and prevention. Their web site is

The primary goal of NFPA is to reduce the worldwide burden of fire and other hazards on the quality of life by providing and advocating scientifically-based consensus codes and standards, research, training, and education.

Additional Info

NFPA has over 300 codes worldwide which are for sale through their web site. These codes cover every conceivable topic including basic fire safety, the National Electrical Code, and life safety. These codes are developed and updated through an open process, ensuring their broad acceptance.

drawing of the NFPA diamond

While NFPA codes cover several aspects of flammable materials pertinent to SDS's, perhaps the most significant is the NFPA 704 Hazard Identification ratings system (the familiar NFPA "hazard diamond" shown on the right) for health, flammability, and instability. The NFPA's Fire Protection Guide to Hazardous Materials, 2010 edition includes NFPA 704, "Standard System for the Identification of the Hazards of Materials for Emergency Response" as well as pertinent information from a variety of other NFPA publications (including NFPA 704 ratings for over 3,000 specific chemicals, information not included with NFPA 704).

What do the numbers and symbols on an NFPA fire diamond mean? The diamond is broken into four sections. Numbers in the three colored sections range from 0 (least severe hazard) to 4 (most severe hazard). The fourth (white) section is left blank and is used only to denote special fire fighting measures/hazards.

NFPA sign kit

NFPA signs and kits are available at Safety Emporium.

At first glance, the HMIS® and NFPA labeling systems appear quite similar. Both have four sections colored blue, red, yellow and white. HMIS® uses colored bars, while NFPA uses colored diamonds. HMIS® attempts to convey full health warning information to all employees while NFPA is meant primarily for fire fighters and other emergency responders.

Some employers use hybrids of the two systems. For example, they will use an NFPA hazard diamond, but the white section is used to denote both personal protective equipment (PPE) and/or special hazards. Both the NFPA and NPCA discourage mixing of the two systems in this manner. OSHA permits one to use any labeling system as long as it meets their labeling performance requirements. Thus, if you use a hybrid system at your location, your employees must be properly trained in using it and be made aware of these potential conflicts.

Health Hazard
the NFPA diamond
4 Very short exposure could cause death or serious residual injury even though prompt medical attention was given.
3 Short exposure could cause serious temporary or residual injury even though prompt medical attention was given.
2 Intense or continued exposure could cause temporary incapacitation or possible residual injury unless prompt medical attention is given.
1 Exposure could cause irritation but only minor residual injury even if no treatment is given.
0 Exposure under fire conditions would offer no hazard beyond that of ordinary combustible materials.
the NFPA diamond
4 Will rapidly or completely vaporize at normal pressure and temperature, or is readily dispersed in air and will burn readily.
3 Liquids and solids that can be ignited under almost all ambient conditions.
2 Must be moderately heated or exposed to relatively high temperature before ignition can occur.
1 Must be preheated before ignition can occur.
0 Materials that will not burn.
the NFPA diamond
4 Readily capable of detonation or of explosive decomposition or reaction at normal temperatures and pressures.
3 Capable of detonation or explosive reaction, but requires a strong initiating source or must be heated under confinement before initiation, or reacts explosively with water.
2 Normally unstable and readily undergo violent decomposition but do not detonate. Also: may react violently with water or may form potentially explosive mixtures with water.
1 Normally stable, but can become unstable at elevated temperatures and pressures or may react with water with some release of energy, but not violently.
0 Normally stable, even under fire exposure conditions, and are not reactive with water.
Prior to 1996, this section was titled "Reactivity". The name was changed because many people did not understand the distinction between a "reactive hazard" and the "chemical reactivity" of the material. The numeric ratings and their meanings remain unchanged.
Special Hazards
the NFPA diamond
This section is used to denote special hazards. There are only three NFPA 704 approved symbols:
OX This denotes an oxidizer, a chemical which can greatly increase the rate of combustion/fire.
SA This denotes gases which are simple asphyxiants. Under the 2012 and earlier editions of NFPA 704 the only gases for which this symbol was explicitly permitted were nitrogen, helium, neon, argon, krypton, and xenon. The 2017 edition (now current), the symbol can also be used for liquified carbon dioxide vapor withdrawal systems or areas where large amounts of Dry Ice are used in confined spaces. The use of this hazard symbol appears to be optional.
W with a bar Unusual reactivity with water. This indicates a potential hazard using water to fight a fire involving this material. When a compound is both water-reactive and an oxidizer, the W/bar symbol should go in this quadrant and the OX warning is placed immediately below the NFPA diamond.
Some organizations use other symbols, abbreviations, and words in the white Special Hazards section. NFPA 704 permits the use of additional symbols, but they must be placed outside of the NFPA diamond. The following symbols are not compliant with NFPA 704, but we present them here in case you see them on an SDS or container label.
ACID This indicates that the material is an acid, a corrosive material that has a pH lower than 7.0.
ALK This denotes an alkaline material, also called a base. These caustic materials have a pH greater than 7.0.
COR This denotes a material that is corrosive (it could be either an acid or a base).
corrosive, hand burned by acid This is a another symbol used for corrosive.
poison, skull and crossbones The skull and crossbones is used to denote a poison or highly toxic material. See also: CHIP Danger symbols and GHS pictograms.
Radioactive The international symbol for radioactivity is used to denote radioactive hazards; radioactive materials are extremely hazardous when inhaled.
Explosive Indicates an explosive material. This symbol is somewhat redundant because explosives are easily recognized by their Instability Rating.

The exact guidelines by which you can place a chemical in one of these four categories are available in the NFPA standard (see Further Reading below).

NOTE: NFPA and other labeling codes (such as HMIS®) are NOT required by OSHA. OSHA has said "...OSHA does not endorse specific services or products. It would, therefore, be inappropriate for OSHA to require a particular labeling system's code on the material safety data sheet." (see this official OSHA interpretation). OSHA does have specific labeling requirements that must be fulfilled, and the hazard classifications that are required run completely counter to the now-obsolete HMIS® III sytem.

SDS Relevance

Flammable solvent storaget cabinets

Store your aerosol cans safely with flammable storage safety cabinets from Safety Emporium.

Many manufacturers include NFPA 704 information on their Safety Data Sheets, but there has never been an OSHA requirement for them do so.

OSHA's adoption of the Globally Harmonized System (GHS) as part of the 2012 revision of the Hazard Communication Standard (29 CFR 1910.1200) changed container labeling requirements to include specific elements including pictograms, hazard statements, precautionary statements and a signal word. For the most part, this harmonized labeling system makes alternate labeling systems such as HMIS obsolete or redundant, however, NFPA 704 information is nice to have as local fire codes may require 704 signage on tanks, doors and other workplace locations.

In a 2013 interpretation letter, OSHA confirmed that SDS authors may include HMIS and NFPA ratings in Section 2 of the SDS as long as they do not contradict or cast doubt on the HCS 2012 classification.

We have emphasized the last part of that statement. Given that NFPA ranks 1 as low and 4 as high hazard whereas the HCS ranks 1 as high and 4 as low, it seems exceedingly likely that even trained employees will be confused if both systems are in simultaneous use, particularly at multi-employer workplaces. For example, using the two systems at the same time could result in a label with an NFPA flammability rating of 4 but a (required) GHS flammability classification of 1 on the same label! Therefore, we strongly discourage employers from using the NFPA system in workplace labeling unless legally required under local fire codes given the potential for confusion with the mandatory OSHA hazard classification and categorization system. At the same time, emergency first responders might like to have this information, so it makes sense for manufacturers to put NFPA ratings on the SDS as long as the difference in this rating system vs GHS is made abundantly clear.

Further Reading

Hazardous Chemicals Rating Chart safety poster

This poster from Safety Emporium contains NFPA numeric ratings for hundreds of common chemicals.

See also: combustible, flammable, health hazard, smoke.

Additional definitions from Google and OneLook.

Entry last updated: Friday, January 6, 2023. This page is copyright 2000-2023 by ILPI. Unauthorized duplication or posting on other web sites is expressly prohibited. Send suggestions, comments, and new entry desires (include the URL if applicable) to us by email.

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