Which description best applies to a substance with an NFPA diamond showing Health: 3, Flammability: 0, Instability: 1?

• A. A mildly toxic, highly flammable, very unstable substance
• B. A highly flammable, non-toxic, highly unstable substance
• C. A non-toxic, non-flammable, stable substance
• D. A highly toxic, non-flammable, slightly unstable substance

Answer: (D)

Verified step by step guidance

1. Understand the NFPA diamond ratings: Health (blue), Flammability (red), and Instability/Reactivity (yellow) are each rated from 0 (minimal hazard) to 4 (severe hazard).
2. Interpret the Health rating of 3, which indicates a substance that is highly toxic and can cause serious or permanent injury.
3. Interpret the Flammability rating of 0, meaning the substance will not burn under typical fire conditions and is considered non-flammable.
4. Interpret the Instability rating of 1, which means the substance is slightly unstable and may become unstable at elevated temperatures or pressures.
5. Combine these interpretations to describe the substance as highly toxic (Health 3), non-flammable (Flammability 0), and slightly unstable (Instability 1).