What system uses numbers 0-4 to indicate relative risk for hazard recognition?

The NFPA 704 System is designed to give immediate visual cues regarding the hazards associated with materials, particularly in emergency situations. This system employs a color-coded diamond shape with four quadrants, each representing different types of hazards: health, flammability, reactivity, and specific hazards. The numbers 0 to 4 indicate the severity of each hazard, where 0 signifies minimal risk and 4 indicates severe risk.

For instance, a material with a health hazard rating of 4 means that it poses a significant threat to health if encountered, while a rating of 0 denotes that it presents no hazard. This allows first responders and others to quickly assess the level of danger and take appropriate precautions.

In contrast, while the placarding system and the United Nations placards provide essential information about transportation hazards, they do not utilize this specific numerical scale. The GHS (Globally Harmonized System) focuses more on chemical classifications and hazard communication but doesn't categorize risk using the 0-4 scale. Therefore, the NFPA 704 System is distinct and crucial for effective hazard recognition and response.