Class 1 hazards are classified based on which of the following characteristics?

Class 1 hazards specifically pertain to explosive materials, and their classification focuses on characteristics related to projection, explosives, blast, or fire. This classification system recognizes the various ways explosives can behave or react, particularly under conditions that may trigger an explosive event.

The characteristics associated with Class 1 materials are critical for understanding their potential risks, such as the impact of blasts, the potential for fragmentation, and the fire hazards they may pose. Proper classification helps in ensuring appropriate storage, handling, and emergency response protocols.

In contrast, the other options such as chemical reactivity, corrosiveness, and irritancy levels relate to other classes of hazardous materials. These characteristics are vital for understanding risks associated with different types of chemicals but are not relevant when discussing Class 1 hazards.