Which exposure route involves breathing in substances?

The exposure route that involves breathing in substances is inhalation. This process occurs when airborne contaminants enter the body through the respiratory system. Inhalation is a critical route of exposure for hazardous materials because it allows substances to quickly enter the bloodstream via the lungs, leading to immediate systemic effects.

Inhalation is particularly significant in situations involving gases, vapors, and aerosols, as these forms can easily be inhaled. Understanding this route is essential for emergency responders and hazardous materials operations, as it helps formulate appropriate protective measures and response strategies for contamination incidents.

In contrast, absorption refers to substances entering the body through the skin, ingestion involves swallowing substances, and injection directly delivers substances into the body through punctures or breaks in the skin. Each exposure route has distinct characteristics and implications for health and safety, making it crucial to recognize inhalation as a primary route in hazardous material incidents.