Injection is defined as taking in materials through a puncture of the skin. Which option correctly identifies this exposure route?

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

Answer: (B)

Exposure routes describe how hazardous materials enter the body. Entry through a puncture in the skin is injection, because the material is introduced directly through a break in the skin and can reach tissues or the bloodstream without going through the mouth or lungs. This bypasses the respiratory and digestive systems, which is why it’s distinct from the other routes: inhalation (breathing in), ingestion (swallowing), and dermal absorption (skin contact—typically without a puncture). A needle-stick or other puncture example illustrates this route clearly.