Injection is an exposure route characterized by which description?

• A. Inhalation
• B. Injection (entry through a puncture in the skin).
• C. Ingestion
• D. Absorption

Answer: (B)

Injection as an exposure route means a contaminant enters the body through a puncture or cut in the skin, such as a needle prick or other sharp object breaking the skin. This pathway bypasses the skin’s outer barrier, delivering substances directly into the tissue and potentially the bloodstream, which can lead to rapid and systemic exposure. Inhalation involves breathing in aerosols or vapors, ingestion means swallowing the substance, and absorption refers to substances crossing the skin without a puncture. The description “entry through a puncture in the skin” most accurately captures what injection is.