What is the main hazard in Class II locations?

In Class II locations, the primary hazard is the presence of combustible dusts. These dusts can accumulate in the air and create an explosive environment when mixed with sufficient quantities of oxygen. Unlike flammable gases, which are typically encountered in Class I locations, Class II locations deal specifically with solid combustible materials.

When dust particles become suspended in the air, they can easily ignite from a spark or flame, resulting in a dust deflagration or explosion. This risk necessitates the implementation of stringent safety measures and equipment that are specifically designed to prevent ignition sources and contain any potential dust explosions.

The other options, while hazardous, do not represent the main concern in Class II environments. For instance, flammable gases pertain primarily to Class I locations, while inert compounds do not pose a combustion risk, and corrosive vapors, though dangerous in their own right, do not match the explosive potential of combustible dust in these settings. Thus, the focus on dust as the primary hazard in Class II locations is critical for ensuring safety and compliance within these environments.