What is defined as injection in the context of hazardous material exposure?

In the context of hazardous material exposure, injection refers specifically to taking materials through skin puncture. This can occur through various means, such as a needle or a sharp object that breaches the skin barrier, allowing hazardous substances to enter the bloodstream directly. This mode of exposure is particularly concerning because it bypasses the body's natural defenses, leading to a rapid and potentially severe systemic effect from the hazardous material.

The other options describe different methods of exposure: inhalation involves breathing in airborne contaminants, ingestion refers to swallowing substances, and absorption is the process where materials pass through membranes, typically the skin or mucous membranes. Each of these routes poses its own risks, but only injection specifically deals with puncturing the skin to introduce a substance into the body.