Vapors that attack mucous membranes are classified as which type of hazard?

• A. Irritants
• B. Carcinogens
• C. Corrosives
• D. Toxins

Answer: (A)

Vapors that attack mucous membranes are irritants. This type of hazard causes local irritation of the eyes, nose, throat, and airways when inhaled. The key effect is discomfort and irritation rather than immediate tissue burning or systemic poisoning. Corrosives, on the other hand, cause tissue damage and chemical burns on contact; carcinogens are linked to cancer risk over time rather than quick mucous membrane irritation; toxins refer to substances with toxic effects that are often systemic rather than limited to irritation of mucous membranes. So the characteristic immediate effect described—irritation of the mucous membranes—points to an irritant hazard.