Construction Health and Safety Technician (CHST) Practice Test

Diffusion is generally considered a passive movement of substances primarily at the molecular level, where molecules move from an area of higher concentration to an area of lower concentration. While diffusion can occur in various biological and physical processes, it is not classified as a typical route for hazardous substances to enter the body.

The primary routes through which hazardous substances commonly enter the human body are through inhalation, where toxic substances are breathed in; absorption through the skin, where harmful chemicals can penetrate the skin barrier; and ingestion, where substances are swallowed and can harm internal organs. Each of these routes involves specific mechanisms that allow substances to enter the bloodstream or tissues, which is why they are critical in the context of health and safety assessments.