What defines a contaminant in the context of hazardous materials?

A contaminant in the context of hazardous materials is defined as a substance that poses a risk of direct injury or exposure to individuals, the environment, or property. This indicates that contaminants can result in harmful health effects, environmental damage, or disruption to safety and functionality in various settings. The characterization of a contaminant underlines the necessity for proper handling, storage, and disposal of hazardous materials to mitigate these risks.

The other choices do not align with this definition. A physical hazard only pertains to the nature of the risk rather than the definition of a contaminant. A substance that is harmless does not qualify as a contaminant, as it implies no risk. Lastly, a type of decontamination agent refers specifically to materials used to remove contaminants, rather than the contaminants themselves. Therefore, defining a contaminant through direct injury or exposure encompasses the essence of the associated hazards effectively.