Combustible Dust in the Workplace

Combustible Dust in the Workplace

Introduction

Any combustible material can burn rapidly when in a finely divided form. If such a dust is suspended in air in the right concentration, under certain conditions, it can become explosible. Even materials that do not burn in larger pieces (such as aluminum or iron), given the proper conditions, can be explosible in dust form.

The force from such an explosion can cause employee deaths, injuries, and destruction of entire buildings. For example, 3 workers were killed in a 2010 titanium dust explosion in West Virginia, and 14 workers were killed in a 2008 sugar dust explosion in Georgia. The U.S. Chemical Safety and Hazard Investigation Board (CSB) identified 281 combustible dust incidents between 1980 and 2005 that led to the deaths of 119 workers, injured 718, and extensively damaged numerous industrial facilities. (Jef et al., 2009)

A wide variety of materials that can be explosible in dust form exist in many industries. Some industry examples include: food (e.g., candy, sugar, spice, starch, flour, feed), grain, tobacco, plastics, wood, paper, pulp, rubber, furniture, textiles, pesticides, pharmaceuticals, dyes, coal, metals (e.g., aluminum, chromium, iron, magnesium, and zinc), and fossil fuel power generation.

Combustible dusts are finely-ground organic or metal particles found in a variety of industries and workplaces. Potentially dangerous accumulations of combustible dust can build up inside process equipment or escape from process equipment and settle on surfaces in the general work area. These accumulations are extremely explosive when dispersed into the air in the presence of commonplace ignition sources, such as standard electrical switches.

Dust explosions can be catastrophic and cause death, injury, and destruction of entire buildings. In many combustible dust accidents, employers and employees were unaware that a hazard existed.

Fortunately, you can take steps to protect employees and others from this possible danger.

Dust explosions can cause large-scale loss of life and catastrophic damage to industrial facilities. Most solid organic materials, as well as many metals and some nonmetallic inorganic materials, will burn or explode if finely divided and dispersed into the air in sufficient concentrations. For example, polishing, grinding, transporting and shaping many of these materials can produce very small particles, which can easily become airborne and settle on surfaces, crevices, dust collectors and other equipment. When disturbed, the materials can generate potentially explosive dust clouds.

Following three catastrophic dust explosions in 2003 that killed a total of 14 workers, the US Chemical Safety Board (CSB) launched a nationwide study of dust explosions in general industry and what can be done to reduce the risks. The CSB study concluded that combustible dust explosions are a serious hazard in American industry, and that existing efforts inadequately address this hazard. (Zalosh 2009)

The Occupational Safety and Health Administration (OSHA) has taken steps in recent years to increase awareness and prevention of combustible dust hazards in the workplace. Sources of ignition may include electrical outlets, industrial vehicles or metal tools laid on hard surfaces that produce sparks. Any of these triggers can cause an explosion if they come ...