What are “hazardous dust” materials?

Hazardous dust materials are defined as fine particulates that can ignite and cause explosions when exposed to ignition sources. These dusts can accumulate in the air and, if ignited, can lead to both flash fires and dust deflagrations, which are rapid but subsonic combustion that can generate strong pressure waves. This is particularly critical in various industries where handling and processing of such materials occur, emphasizing the need for proper ventilation, dust control measures, and precautions to mitigate explosion risks.

The other options do not align with the definition of hazardous dust. Liquid substances that evaporate quickly can be flammable, but they do not pertain to dust. Solid materials that are deemed safe to handle do not pose a risk regarding dust hazards. Non-combustible powders used in construction may not ignite or cause explosions, thus not qualifying as hazardous dust. Therefore, the correct identification of hazardous dust aligns specifically with its capacity to ignite and generate significant hazards in the presence of ignition sources.