Agricultural operations generate a lot of airborne particles, including mineral, field, and barn dusts, chaff and pollen. Much of these agricultural dusts are around 10 micrometers in diameter. (For comparison, an average human hair is 50 to 70 micrometers across.) Particles that size can move past the nose and throat and lodge in the lungs, causing serious respiratory harm. Prolonged exposure to dust can cause many health problems, including pneumoconiosis, a lung disease that restricts breathing.
The most acute danger of agricultural dust, however, is that of explosion. The accumulation of grain dust in a facility poses this critical risk that farmers have known about for ages. If enough dust is present in an enclosed space, it can be ignited by a spark, cigarette, overheated bearing, or many other small ignition hazards. A grain dust explosion can be violent enough to destroy a grain elevator, mill or other such facility.
Grain dust accumulation and ignition sources are regulated by OSHA standards to prevent explosions. (See, 29 CFR 1910.272.) Employers must minimize dust accumulation, and failure to comply with regulations can bring serious fines. It is generally accepted that a layer of dust 1/8 of an inch thick is enough to fuel an explosion.
The National Fire Protection Association extends these cautions beyond grain elevators and mills. These include any facility handling agricultural materials, such as “facilities that receive, handle, process, dry, blend, use, mill, package, store, or ship dry agricultural bulk materials, their by-products, or dusts. . . “