NFPA 654 addresses facilities handling combustible dust including grain elevators, flour mills, chemical plants, and wood product mills. Combustible dust explosions occur in three conditions: combustible dust, oxygen, and ignition source. Prevention requires controlling any one of these three elements. Dust collection systems must be properly designed, maintained, and cleaned. Ignition sources including friction, static electricity, and hot surfaces must be controlled. Electrical equipment in areas with combustible dust must be rated for the hazard. Grounding and bonding prevents static electricity accumulation. Housekeeping controls dust accumulation on surfaces that could be resuspended. Training and safety procedures ensure workers understand the hazard.