Which of the following chemical hazards can be particularly hazardous to workers in confined spaces?

• A. Toxic gases such as carbon monoxide (CO)
• B. Dilute aqueous solutions of sodium chloride (NaCl)
• C. Non-toxic dusts such as talc
• D. Inert gases such as nitrogen (N_2)

Answer: (A)

Verified step by step guidance

1. Understand the context: Confined spaces are areas that are not designed for continuous occupancy and have limited means of entry or exit, which can lead to accumulation of hazardous substances.
2. Identify the types of hazards listed: toxic gases (e.g., carbon monoxide), dilute aqueous solutions (e.g., sodium chloride), non-toxic dusts (e.g., talc), and inert gases (e.g., nitrogen).
3. Evaluate each hazard's potential risk in confined spaces: Toxic gases like carbon monoxide are dangerous because they can accumulate without being detected, leading to poisoning.
4. Consider why dilute aqueous solutions and non-toxic dusts are less hazardous: They generally do not produce harmful vapors or displace oxygen significantly in confined spaces.
5. Recognize that inert gases, while non-toxic, can still be hazardous by displacing oxygen and causing asphyxiation, but toxic gases like carbon monoxide pose a direct chemical poisoning risk, making them particularly hazardous.