HMIS - Yellow or Orange Bar

The ACA has released three versions of the HMIS since its inception to meet the OSHA standards for labeling. The third bar is where most of the changes have occurred. This bar can either be presented as yellow or orange, and it refers to physical and reactivity hazards. The ACA used OSHA's criteria for determining physical hazards when creating this section of the label. The hazards values are broken down into the following categories:

0 - Minimal hazard.

• Non-explosive hazards. Under normal conditions, or even when exposed to fire, these chemicals will remain stable, and are not reactive with water.

1 - Slight hazard.

• Chemicals that are stable under normal conditions, but could become unstable at extreme temperatures or conditions. These chemicals may react with water, but if so, it is not a violent reaction.

2 - Moderate hazard.

• Chemicals that are not normally stable and can easily undergo a violent chemical change; however, they do not detonate. These chemicals might have a violent reaction with water, or they might form potentially explosive mixtures.

3 - Serious hazard.

• Chemicals that are capable of exploding or detonating; however, they require a large source for initiation or a large heat source. This also includes chemicals that are sensitive to shocks at higher temperatures or pressures, and chemicals that will explosively react with water without requiring a heat source.

4 - Severe hazard.

• Chemicals that can easily explode or detonate at normal temperatures and pressures, and that are sensitive to mechanical or localized shock.

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