Cooperative Personnel Services Firefighter (CPS) Practice Exam 2026 - Free Firefighter Exam Questions and Study Guide

The correct answer is that secondary explosions generally pose the greatest risk in dust environments. In contexts involving combustible dust, primary explosions can initiate, but secondary explosions typically cause more significant damage and danger.

A primary explosion occurs when an initial ignition source sets off the dust cloud, leading to an immediate blast. However, secondary explosions are initiated by the disturbance of already settled dust as a result of the primary explosion. This can send more dust into the air, creating an even larger and more dangerous explosion. Secondary explosions tend to have a much broader reach and can cause severe damage to structures and personnel, often resulting in devastating consequences.

While primary explosions are concerning, it is the aftermath and subsequent events that can exacerbate safety risks. This highlights the critical importance of controlling dust accumulation in environments where combustible dust is present to mitigate not just the first explosion, but to prevent the potential for secondary explosions that can follow. Other types, like propagating explosions, are important in their context but do not typically represent the same level of threat as secondary explosions in these specialized environments where dust accumulation is a key factor.