Inhalation exposure occurs through which route?

• A. Through the mouth or gastrointestinal tract
• B. Through the lungs
• C. Through the skin
• D. Via the bloodstream

Answer: (B)

Inhalation exposure happens when hazardous materials are breathed in and reach the lungs. The lungs provide a direct entry point with a large surface area and a rich blood supply, so substances like gases, vapors, or fine dusts can be rapidly absorbed into the bloodstream through the alveolar membrane. This is why inhalation is a major route of exposure and can lead to both local respiratory effects and systemic toxicity once the contaminant enters the bloodstream. By comparison, entry through the mouth into the gastrointestinal tract is ingestion, entry via the skin is dermal absorption, and substances can reach the bloodstream only after entering the body through one of these routes. An example is chlorine gas, which can be inhaled, irritate the lungs, and be absorbed quickly, potentially causing systemic effects. To prevent inhalation exposure, use appropriate respiratory protection and ventilation.