What types of hazardous materials can be transported by bus?

The correct answer highlights the specific regulations regarding what types of hazardous materials can be transported by bus, particularly in the context of safety and regulatory compliance. Small-arms ammunition that is labeled ORM-D (Other Regulated Materials-Domestic) and emergency supplies are considered lower-risk items and are permitted under certain conditions. This makes them suitable for transport in a bus since the potential for dangerous incidents is minimized compared to other types of hazardous materials.

When transporting hazardous materials, public safety is a major concern. Items classified under ORM-D are subject to less stringent regulations because they pose a lower risk during transportation. In contrast, the other options include materials that are generally considered more hazardous and are typically not allowed for transport by bus due to stricter safety regulations. For example, explosive gases and flammable liquids pose significant risks in terms of combustion and explosion, while chemicals, pesticides, and radioactive materials have even more stringent regulations surrounding their transport and are not commonly authorized for bus transport. Hence, the selection of small-arms ammunition and emergency supplies is aligned with guidelines that prioritize safety while still allowing for necessary transport needs in specific contexts.