Safety in the Chemistry Laboratory
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On the Differences between the NFPA and HMIS/HMIG Hazard Labeling Systems

Both the NFPA Hazard Identification System and the Hazardous Material Identification Guide (HMIG or HMIS) may be used to comply with the labeling requirement of the OSHA Hazard Communication Standard (HCS). These systems, although similar, differ in some important respects.

Similarities

• Both systems have three color-coded fields to indicate the flammability (red), health (blue), and reactivity (yellow) hazards associated with the material.
• Both use a system of five numbers, ranging from 0 to 4, to indicate the severity of hazard, with 0 being the least and 4 being the most hazardous.

Differences

• They differ in layout -- NFPA uses four diamonds, HMIG uses vertically stacked bars.
• The differ in interpretation of the fourth, white field (special handling in the NFPA system; protective equipment in the HMIG system).
• Possibly the most significant difference, however, has to do with the intended audience for each of the systems. The HMIG (or HMIS) was devised as an HCS compliance tool, and has employees who must handle hazardous chemicals in the workplace as the intended audience. The NFPA system was designed to alert fire fighters arriving on the scene of a fire to the hazards associated with materials present at that location. Therefore, the numbers assigned in the NFPA system assume that a fire is present. No such assumption holds in the HMIG/HMIS system. For this reason, the numbers that are assigned to the flammability, health, and reactivity hazards may differ between the NFPA and HMIG systems, even for the exact same chemical. And note that this applies to the true NFPA labeling system, not necessarily the hybrid, in-house system we use in the general labs at the University of Oregon.