What do the numbers 0 through 4 represent in the OSHA hazmat labeling system?

• A. The degree of hazard; 0 - minimum; 1 - slight; 2 - moderate; 3 - serious; 4 - severe
• B. The color coding used for hazard labeling
• C. The size of the container
• D. The degree of PPE required for handling

Answer: (D)

The numbers 0 through 4 express how severe the hazard is in each category of the hazmat rating system. They show the level of danger a material poses to health, flammability, and instability, with 0 meaning no hazard and 4 indicating a severe hazard. This quick scale helps responders judge risk and decide on protective actions, containment, and whether to evacuate or isolate an area. Importantly, those numbers do not specify what level of personal protective equipment to use; PPE is chosen from the material’s safety data sheet and the site’s risk assessment, not from the numeric rating itself. The numbers are about potential harm, not the equipment or the container size, etc.