Combustible dust has long been recognized as having the potential for catastrophic events that may result in loss of life and extensive property damage. Materials that may form combustible dust include metals (such as aluminum and magnesium), wood, coal, plastics, biosolids, sugar, paper, soap, dried blood, and certain textiles. The U.S. Chemical Safety and Hazard Investigation Board ("CSB") has identified 281 combustible dust fires and explosions since 1980 – causing nearly 1,000 fatal or serious injuries. These incidents occurred in 44 states, mostly in food processing facilities or in those involving paper or wood dust.
In many combustible dust incidents, employers and employees were unaware that a hazard even existed. A combustible dust explosion hazard may exist in a variety of industries, including: 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. There are often two types of explosions involved:
Primary (when dust suspension is ignited and explodes); and
Secondary (when dust accumulations on floor and surfaces ignites from primary explosion).
The secondary explosions are often more deadly and damaging, and chain reactions involving dust suspended in air are common.
In 2008, one such event – the fatal explosion at the Imperial Sugar factory in Georgia – turned attention back to this issue in a big way. Activity included the involvement of the United States Congress, which was critical of the failure of the Occupational Safety and Health Administration ("OSHA") to respond to the known hazard with a specific standard to help mitigate risks. OSHA regulations were called insufficient because they failed to regulate dusts other than grain adequately. During the 110th Congress, Congress sought to force adoption of fast-track regulation to govern all combustible dusts. As discussed below, despite the change in executive branch governance, this remains a highly contentious issue and regulations are not currently on the OSHA agenda. Congress has, once again, introduced legislation to force promulgation of a combustible dust rule for OSHA-regulated general industry. This paper also includes a discussion of relevant standards of the Mine Safety and Health Administration ("MSHA") concerning combustible and respirable coal dust.
As a general rule, OSHA normally has codified specific standards where there is a demonstrated significant risk and a feasible means of controlling such risks. Such specific safety and health standards serve as mandates to ensure compliance on a worksite by the primary employer, as well as to share information with, and ensure compliance by, contractors and/or non-employees who may be present at the worksite. However, OSHA's rulemaking process has become highly complicated and litigious, resulting in timeframes of a decade or more before a rule runs the gamut from an advance notice of proposed rulemaking to a final rule. Even then, a rule may be judicially challenged by aggrieved stakeholders, extending the process for several more years.