NFPA 704 Diamond Information: Blue Segment
Blue region - Health Hazard
The blue region of the RTK diamond indicates health hazard and may contain either a 0, 1, 2, 3 or 4. These numbers indicate the level of health exposure risk, and can be interpreted as follows:
- 4 Very short exposure could cause death or major residual injury (e.g., hydrogen cyanide).
- 3 Short exposure could cause serious temporary or residual injury (e.g., chlorine gas).
- 2 Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury (e.g., chloroform).
- 1 Exposure would cause irritation with only minor residual injury (e.g., turpentine).
- 0 Poses no health hazard, no precautions necessary. (e.g., lanolin).