HAZMAT Technician Practice Exam 2025 - Free HAZMAT Technician Practice Questions and Study Resource.

The term 'flammable' refers to the concentration range at which a substance can ignite, which is accurately captured in the answer choice. In hazardous materials contexts, flammability relates to how a substance can form a mixture with air that is capable of sustaining combustion. This concept is crucial for identifying and managing risks associated with materials that can catch fire under specific conditions.

When a substance has a specific concentration range that can ignite, it means that there are particular proportions of that substance mixed with air that will allow for combustion. If the concentration is too low or too high, combustion may not occur. Therefore, understanding this range is vital in safely handling and storing flammable materials to prevent fires or explosions.

Other options may touch on aspects related to fire but do not define flammability correctly. The idea of a substance's ability to explode, while concerning, falls under different classifications of reactive hazards. The temperature at which a substance ignites, commonly referred to as its flash point, is related but distinct from the definition of flammability. Lastly, the rate at which a substance combusts is more about the kinetics of burning rather than flammability itself.