The NFPA 704 diamond is a color-coded label that shows the health, flammability and instability hazards of a material for emergency responders.
The NFPA 704 diamond, often called the fire diamond or hazard diamond, is a color-coded label that shows at a glance how hazardous a material is during a fire or other emergency. It comes from NFPA 704, the Standard System for the Identification of the Hazards of Materials for Emergency Response, published by the National Fire Protection Association.
The diamond is divided into four colored sections. Three of them carry a number from 0 to 4, where 0 means minimal hazard and 4 means severe hazard. The fourth section shows special hazards. The label is posted on buildings, storage rooms, tanks and containers so that firefighters and other responders can quickly decide how to approach an incident.
NFPA 704 is not an OSHA regulation, but many state and local fire codes require it for facilities that store hazardous materials. It is designed for emergency response, not for day-to-day worker hazard communication.
Shows how dangerous short-term exposure is during an emergency. A 4 means very brief exposure could cause death or major injury. A 0 means no hazard beyond that of ordinary combustible material.
Shows how easily the material will burn. A 4 means it vaporizes and burns readily at normal temperatures, like propane. A 0 means it will not burn under normal fire conditions. Ratings are based largely on flash point. See flammable liquids.
Shows how likely the material is to react violently or explode, for example from heat or shock. A 4 means it can detonate at normal temperatures and pressures. A 0 means it is normally stable, even in a fire. This section was once called reactivity. See explosion hazard.
Uses symbols rather than numbers. The standard recognizes three:
Other symbols are sometimes added by users, but they are not part of the standard.
NFPA 704 and the Globally Harmonized System (GHS) used in OSHA's Hazard Communication Standard number hazards in opposite directions. In NFPA 704, 4 is the most severe. In GHS hazard categories, Category 1 is the most severe. This difference often confuses workers.
The two systems serve different purposes. GHS labels and the safety data sheet (SDS) tell workers about a chemical's hazards during normal use and how to protect themselves. The NFPA diamond gives responders a quick summary of acute hazards during a fire, spill or release. Employers should train workers on both if both appear in the workplace, and make sure NFPA ratings never replace the required GHS labels.
A water treatment plant stored chlorine gas cylinders and sodium hypochlorite in separate rooms. During a routine fire inspection, the local fire marshal noted that neither room had NFPA 704 placards. The plant posted diamonds on both doors. The chlorine room was marked with a high health rating, a 0 for flammability and the OX symbol.
Months later, a contractor reported a strong chlorine odor. Arriving firefighters saw the placard, recognized the toxic and oxidizing hazards, and entered only in full protective equipment with self-contained breathing apparatus. They isolated a leaking valve without anyone being exposed.
Each number rates a hazard from 0 to 4. A 0 means minimal hazard, and a 4 means severe hazard.
No. OSHA requires GHS-aligned labels and safety data sheets. NFPA 704 placards are usually required by local fire codes instead.
It means the material reacts dangerously with water, so water should not be used on it in a fire or spill.
Part of SafetyIQ's EHS glossary: plain-English definitions of workplace health and safety terms.
> Keep learning
> See it in action
Capture hazards, run inspections, track training and close out corrective actions in one platform built for high-risk, field-heavy work.
Book my free demo
Get a demo built around your sites, your teams, and the way your people work.
EHS, journey, and fatigue management software for field-heavy teams.
.png){kind=logo}
.png)