Which of the following is a chemical toxic agent?

• A. Lead
• B. Radiation
• C. Bacteria
• D. Virus

Answer: (A)

The key idea is identifying what counts as a chemical toxicant versus other hazard types. Lead is a chemical toxic agent because it is a chemical substance that can cause harm through its chemical properties and interactions in the body (for example, disrupting neurological development and enzyme function). The danger comes from the substance itself, not from a living organism or from physical energy.

Radiation, while hazardous, is a physical agent that injures tissue through energy transfer rather than chemical interaction. Bacteria and viruses are biological agents that cause disease through infection or biological toxins they may produce, not through chemical toxicity of a substance. Therefore, the example that fits a chemical toxic agent is lead.