Which of the following best describes a controlled hazardous material?

A controlled hazardous material is one that poses potential risks to human health and the environment but can be managed appropriately through specific guidelines and regulations. This includes requirements for proper labeling to indicate hazard levels and necessary precautions, as well as training for workers who handle such materials. The labeling informs users of the nature of the risks and the necessary safety measures to undertake, ensuring that individuals are equipped with the knowledge to handle these substances safely.

In contrast, materials posing no risk are not classified as hazardous at all, while those prohibited entirely are banned from use due to their extreme danger. Furthermore, any material that can be safely handled with no precautions would not qualify as hazardous, as a controlled hazardous material inherently requires some form of precautionary measures to mitigate its risks. Thus, option C accurately captures the essence of what makes a material "controlled" in the context of hazardous substances.