Which of the following is NOT considered a chemical hazard?

The answer identifies biological agents as the option that is not considered a chemical hazard. Chemical hazards are typically defined as substances that could result in harm due to their chemical properties. This includes a wide range of materials such as harmful gases, solids, and liquids that can cause toxic effects, environmental damage, or fire hazards.

Chemicals and poisons, along with fumes and smoke, fall under this category as they consist of harmful substances that can adversely affect health or the environment. On the other hand, biological agents refer to microorganisms or their toxins that can cause disease in humans or other living organisms. Since they primarily involve pathogenic organisms rather than chemical substances, they are classified separately from chemical hazards.

Explosives, while they can interact chemically and have chemical properties, are specifically categorized as explosives due to their potential to cause physical damage through explosive reactions, rather than being considered under the category of chemical hazards. Thus, biological agents are distinguished from chemical hazards, confirming why the correct choice is that they are not considered a chemical hazard.