Final answer:
Used munitions picked up by a truck for disposal are considered hazardous waste because of potential threats to public health and the environment, and require proper management as stipulated by the RCRA and sometimes the Atomic Energy Act.
Step-by-step explanation:
When a truck picks up used munitions for disposal, the used munitions become hazardous waste. Hazardous waste is defined as waste that presents substantial or potential threats to public health or the environment. Used munitions may contain dangerous substances like explosive materials or toxic chemicals, which could be harmful if not treated or disposed of correctly. Under the Resource Conservation and Recovery Act (RCRA) and in some cases the Atomic Energy Act, such waste must be managed to ensure it is neither harmful to human health nor the environment. Therefore, the correct answer is (1) hazardous waste.