What constitutes a "hazardous waste" under the MMR?

The correct response identifies that "hazardous waste" under the Military Munitions Rule (MMR) refers specifically to military munitions that either exhibit hazardous characteristics or are discarded. This definition is crucial because it encompasses both munitions that possess inherent properties making them dangerous, such as toxicity or reactivity, as well as those that are no longer needed or are improperly disposed of, transforming them into a waste category that requires careful management.

By focusing on hazardous characteristics, the MMR effectively prioritizes identification and risk mitigation for materials that could pose a threat to human health and the environment. This definition is essential in regulatory contexts, as it helps ensure that adequate handling, storage, and disposal protocols are followed to minimize hazards associated with military munitions.

The other choices, while they touch upon waste categories, do not accurately define what constitutes hazardous waste according to the MMR. They either broaden the definition too far, suggest exclusions that are not applicable in the context of hazardous waste management, or introduce arbitrary criteria, such as time limits, which are not relevant under the established regulations. Thus, option A stands out as the precise definition set forth by the MMR.