704 Hazardous Materials Signs or Hazmat Signs are recognized as National Fire Protection Association (NFPA) diamonds that indicate the danger of a specific substance. This particular hazmat sign possess as an indicator to individuals dealing with carbon dioxide or CO2.
According to the NFPA, a 704 Hazmat sign is to be placed at the entrance of any room that might contain a potential CO2 leak. The National Fire Protection Association established their NFPA 704 Diamond Placard to inform rescue workers if equipment is required and whether they need to take special precautions.
The blue region of the sign illustrates the level of health hazard caused to an individual. Level three means that it can cause serious or permanent injury. The red region of the sign illustrates the flammability hazard. Level zero means that it will not burn you. The yellow region of the sign illustrates the instability hazard. Level zero means the CO2 is very stable. The white region of the sign is reserved for a special hazard and the SA illustrated on this region stands for Simple Asphyxiant.