A fine (small) particles of dry matter. Dusts can be generated by handling, crushing, grinding, rapid impact, detonation, and breakdown of certain organic or inorganic materials, such as rocks, ore, metal, coal, wood and grains. Dusts can form a cloud or suspension in air, but the material tends to settle to the ground evenly rather than diffuse (migrate) throughout an area like a vapor. Dusts do not tend to flocculate (clump together in fluffy masses). The term fumes is sometimes used to refer to airborne dusts. Dusts are different than vapors and mists. Dusts are comprised of solid particles, each of which consists of large number of atoms or molecules of a material that is not normally volatile. Of course, dusts and vapors may sometimes be intermingled. Additional Info: Dust particles may be small enough that they are respirable, capable of being drawn deep into the lungs when you take a breath. Some dusts, such as certain forms of asbestos and coal dust, remain lodged deep inside the lungs where they can eventually cause cancer or other chronic health effects such as emphysema, pneumoconiosis and bronchitis. For example, the American Cancer Society has stated that exposure to asbestos in combination with cigarette smoking increases an individual's lung cancer risk nearly 60 times. At the very least, most dusts are respiratory irritants. Even "natural" products such as moldy hay, bird droppings etc. contain spores that can cause a variety of nasty lung diseases as well. Woodworkers should pay attention to Clarification of OSHA's Hazard Communication Standard with regards to the carcinogenicity of wood dust, too. Other dusts can form explosive mixtures in air. One doesn't ordinarily think about everyday items such as flours or grain as being explosive. But when these combustible materials are reduced to a dust, they have an extremely high surface area and can burn quite rapidly. When the concentrations of air and dust fall within the explosive limits and are ignited, the resulting fire and explosion can be astounding. Essentially any material that can burn can explode as a dust! Grain dust explosions are quite powerful and deadly. Take a look at the aftermath of a deadly accident. A 2006 study by the US Chemical Safety Boardfound 281 dust fires and explosions over a 25-year period that took 119 lives and caused 718 injuries. 24% of those were in the food industry. 71% of the incidents resulted in injuries or fatalities. See: Why an MSDS for sugar isn't as silly as most people think? Dust explosions require five elements: The presence of a combustible dust. The materials can be organic, or even a powdered metal such as aluminum or magnesium. Particle size plays a key role here. Smaller particles have larger surface areas, which makes them more chemically reactive and easier to ignite. There must be a source of oxygen, usually air. The dust must be dispersed into the air. This can happen during mixing and transfer operations, for example. (1) There must be a source of ignition. In many cases, the dust can generate its own static electricity and in others, an open flame or spark could cause ignition. (2) Confinement. Most buildings, process equipment, and ventilation duct work offer sufficient containment to turn a fireball into an explosive situation. Keep in mind that dust explosions can kick up even more dust, making them auto-catalytic in nature, and greatly increasing the force of the original event. In light of CSB 2006 study mentioned above, there were calls for OSHA to issue acombustible dust standard. A rather polarized debate attracted attention in the US Congress, and finally, in 2009, OSHA announced it was initiating a comprehensive rulemaking on combustible dust. On November 10, 2009, OSHA published an advanced notice of proposed rule-making covering dust in the workplace which begins with informal stakeholder meetings in Washington, DC on December 14th, 2009 and later dates to be announced. MSDS Relevance: MSDS's usually provide information regarding how to avoid the formation of dust or precautions you should take when working with dusts of the material. Three general ways to avoid being exposed to dusts are: (1) Control dust at its source using engineering controls. This can involve using a dust collection system on a grinder or saw or simply wetting the material with water. If you do not generate airborne dust in the first place, it can't pose an inhalation hazard. (2) Local exhaust ventilation provided by a ventilating blower or fume extractor can remove any dust that gets into the air and help keep the concentration to more acceptable levels. (3) Appropriate personal protective equipment (PPE) such as dust masks or respirators when working with dusts of any nature, but especially those that are hazardous. Also, wear goggles to minimize damage to your eyes. See also: Asthma, Fume, Smoke