A Hazard Class of 3, within the United Nations (UN) Labeling System indicates a:

A Hazard Class of 3, within the United Nations (UN) Labeling System indicates a:

• A. Flammable gas.
• B. Flammable solid.
• C. Flammable/combustible liquid.
• D. Poisonous liquid.

Answer: (C)

Hazard Class 3 signals liquids that can ignite easily. In the UN labeling system, Class 3 is for flammable liquids—substances whose vapors can form an ignitable mixture with air at relatively low temperatures. The phrase “flammable/combustible liquid” is used to cover the full range of liquids within this class, from those with very low flash points (highly flammable) to those with higher flash points that are still considered combustible under regulatory terms. This is why it’s the best answer: the focus is on liquids that pose a fire hazard through ignition of vapors, not on gases, solids, or poisons. For contrast, a flammable gas belongs to a different class, a flammable solid to another, and a poisonous liquid falls under toxic substances, so those options don’t describe Class 3. In practice, handling Class 3 liquids requires controlling ignition sources, ensuring proper ventilation, and using grounding/bonding and appropriate labeling.

Hazard Class 3 signals liquids that can ignite easily. In the UN labeling system, Class 3 is for flammable liquids—substances whose vapors can form an ignitable mixture with air at relatively low temperatures. The phrase “flammable/combustible liquid” is used to cover the full range of liquids within this class, from those with very low flash points (highly flammable) to those with higher flash points that are still considered combustible under regulatory terms. This is why it’s the best answer: the focus is on liquids that pose a fire hazard through ignition of vapors, not on gases, solids, or poisons.

For contrast, a flammable gas belongs to a different class, a flammable solid to another, and a poisonous liquid falls under toxic substances, so those options don’t describe Class 3. In practice, handling Class 3 liquids requires controlling ignition sources, ensuring proper ventilation, and using grounding/bonding and appropriate labeling.