Which of the following is a characteristic of the injection route of exposure?

• A. Substance enters directly into the bloodstream; causes the most severe effects
• B. Substance enters through the respiratory system; high severity
• C. Substance enters through the skin; low severity
• D. Substance enters through the eyes; may cause systemic poisoning

Answer: (A)

Injection delivers the substance directly into the bloodstream, bypassing protective barriers like the skin and mucous membranes. This quick entry into circulation means the chemical is distributed rapidly to organs, often producing systemic effects and, for many substances, more severe toxicity at lower doses than other routes. That immediacy and systemic reach is why this option best describes the injection route.

Inhalation involves the respiratory system, not direct bloodstream entry; dermal exposure occurs through the skin and is typically slower as the substance must cross skin barriers; ocular exposure occurs through the eyes and may cause local effects or, in some cases, systemic effects but not via direct bloodstream entry.