On a hazardous information label, what does the color blue indicate?

• A. Health hazard
• B. Environmental hazard
• C. Flammable hazard
• D. Toxic hazard

Answer: (A)

Blue on a hazardous information label signals a health hazard. In the NFPA 704 system, the diamond is split into four colors: blue for health, red for flammability, yellow for reactivity, and white for any special precautions. The blue section carries a number from 0 to 4 that shows how severe the health risk is from exposure. A higher number means greater potential for harm through inhalation, skin contact, or ingestion, including both immediate effects like irritation and longer-term issues. This color helps you determine what protective measures to use—like appropriate PPE, ventilation, and handling procedures—to minimize health risks. The other colors correspond to different hazards: red indicates flammability, yellow indicates reactivity, and white covers special hazards. Environmental hazards aren’t conveyed by the blue health panel in this system, and health risk also encompasses what people typically mean by toxicity.