Federal Emergency Management Agency (FEMA) Standardized Awareness Practice Test

Which of the following is an example of a tertiary explosive?

1. TNT

2. Ammonium perchlorate

3. C4

4. Dynamite

The correct answer is: Ammonium perchlorate

The correct answer is ammonium perchlorate, which is classified as a tertiary explosive. To understand why this is the right choice, it's important to recognize how explosives are categorized based on their sensitivity, velocity of detonation, and stability. Tertiary explosives are relatively insensitive and require a substantial initiation force to detonate. Ammonium perchlorate, commonly used as an oxidizer in solid rocket propellants, fits this category because it is stable under normal conditions and needs a strong detonating agent to initiate a chain reaction. In contrast, TNT (trinitrotoluene), C4, and dynamite are examples of primary or secondary explosives, which are more sensitive and can detonate under less extreme conditions. Primary explosives are highly sensitive to heat, shock, or friction, while secondary explosives, although less sensitive than primaries, still require less energy to initiate than tertiary explosives. This distinction is crucial in safety and handling practices in industries dealing with explosives, as it informs how they can be transported or stored, as well as the precautions necessary during use. Understanding the characteristics of ammonium perchlorate as a tertiary explosive helps in recognizing its applications and the safety measures required to handle it effectively.