The general routes of entry for human exposure to hazardous materials are:

• A. Inhalation, Ingestion, Radiation, and Injection
• B. Injection, Infection, Radiation, and Adsorption
• C. Inhalation, Ingestion, Absorption, and Injection
• D. Absorption, Dilution, Injection, and Ingestion

Answer: (C)

Exposure to hazardous materials generally occurs through four routes: inhalation, ingestion, absorption, and injection. Inhalation involves breathing in contaminated air, vapors, dust, or aerosols, which is why respiratory protection and proper ventilation are central to safety. Ingestion happens when contaminants enter the body by swallowing, often from touching the face or hands with contaminated fingers or food and drink. Absorption occurs when a chemical passes through the skin or mucous membranes, so wearing appropriate gloves and protective clothing helps prevent dermal exposure. Injection is when a substance is introduced under the skin by a puncture or needle-stick, making careful handling of sharps and spill control essential.

The other options mix terms that aren’t routes of entry for hazmat exposure. Radiation is a hazard modality rather than a general entry route for chemical materials, infection isn’t a chemical exposure pathway, and concepts like adsorption or dilution describe processes, not entry routes.