What hazard class is typically associated with materials that are reactive and can explode under certain conditions?

The hazard class associated with materials that are reactive and can explode under certain conditions is classified as explosives. Explosives are substances that can undergo a rapid chemical reaction, creating a significant amount of gas and heat, which can result in an explosion. This class includes items such as dynamite, fireworks, and certain kinds of ammunition. The key characteristic is their ability to release a large amount of energy in a very short time, which can be triggered by heat, shock, or other forms of energy.

Understanding explosives is crucial for emergency responders, as these materials require specialized handling and containment procedures to mitigate the risks they pose. Training on identifying these materials and recognizing their behavior under various conditions helps ensure safety during hazardous materials incidents.