Final answer:
A hazard is something that could be a possible danger, whether on the road or as a substance like hazardous waste that poses a risk to health and the environment.
Step-by-step explanation:
The definition of a hazard is D. A road user or road condition that could be a possible danger. This can refer to various signs, conditions, or situations that present a potential risk and should be cautiously approached or avoided to prevent accidents or harm. In environmental context, a hazard often relates to substances or situations that pose risks to health, such as contaminants and hazardous waste.
Hazardous waste, as defined under the Resource Conservation and Recovery Act (RCRA), is any solid waste that due to certain characteristics can cause significant harm to human health or the environment if not managed properly. This includes waste with properties of ignitability, corrosivity, reactivity, or toxicity, and it must be treated, stored, and disposed of using special methods to mitigate those risks.