Dust accumulation within the workplace can combust and result in workplace explosions and cause fires that rage out of control. Employers have a responsibility to their employees and others that requires them to prevent the accumulation of explosive dust in the workplace. When employers fail to adhere to established safety protocols and maintain dust collection and removal systems, they are negligent in their duties.
Types of Combustible Dust
Wood dust, grain dust, and coal dust are some of the most dangerous types of dust in the workplace. Other carbon dust, and those from the production of plastics or additives also pose a risk. It is also possible for aluminum and magnesium dust to ignite and explode. Essentially, any organic dust including sugar, flour, soap, or other biosolids can combust when contact with an ignition source occurs.
This means that workers in a wide range of industries are at risk of suffering severe burns or explosive injuries when dust combusts. This includes workers in agriculture, food production/processing, textile production, furniture production, metal processing, paper processing, etc. It also includes workers in pharmaceutical production, recycling, and coal handling and processing.
What Causes Dust to Combust
Tiny particles of dust can accumulate within storage containers, on warehouse floors, within the ductwork, or within the bowels of machinery. When sparks or open fire are present, these particles can combust starting a chain reaction. In an open environment, this often results in a fire. If the environment is enclosed, the result can be an explosion.
It does not take a significant amount of dust to cause a fire or explosion. The finer the dust particles, the greater the risk of a potential explosion. In most cases, dust accumulation of 1/32 of an inch is sufficient to cause a fire. This is roughly the same thickness of a dime. The risk increases if more than 5% of the work area is covered with a layer of dust. This includes work surfaces, rafters, pipes, and other horizontal surfaces where dust can accumulate.
The Risk of Fire and Explosion
One of the most significant dust explosions occurred in 2008 when the Imperial Sugar refinery in Port Wentworth, GA caught fire and exploded. That incident claimed 14 lives and injured 36 others. Nationwide, approximately 500 dust-related fires and explosions occur in the United States. In most of these incidents, there is a history of “near misses” where safety protocols were either ignored or improperly corrected.
One of the greatest risks of a dust explosion is secondary explosions. As the pressure wave from the first explosion expands, this can stir up dust within other containers or enclosed spaces within a facility. This creates a chain reaction of explosions that can quickly envelop a facility and any workers caught in the path of the explosion.
OSHA combustible safety standard 29 CFR 1910 addresses the hazards of combustible dust in the workplace. The standard and its subparts require employers to control dust accumulation in the workplace and conduct regular inspections of machinery, storage containers, warehouses, etc.
The standards require employers to maintain clear exit routes and updated emergency action plans. They must also maintain fire prevention and suppression systems. It is also vital that employers provide proper training in material handling and processing, as well as inventory storage and disposal of waste. These standards apply to a wide range of industries including sawmills, bakeries, paper mills, sugar processing facilities, coal producers, etc. Failure to adhere to these established safety standards can result in fines and other penalties. Employees who discover safety violations can report them to OSHA without the threat of penalty or retaliation from the employer. Workers who are injured can file workers’ compensation claims.
Preventing Dust Fires
Dust fires and explosions require a type of combustible dust, ignition source, and oxygen. Thus, preventing fires means controlling these three key factors. This requires employers to implement regular inspections for hazardous dust, perform routine maintenance to remove dust, and install and maintain adequate dust removal systems.
Employers must thoroughly inspect the entire worksite for dust residue. This includes both open and hidden areas where dust can accumulate. Employers must also train employees to safely remove dust so that they do not generate dust clouds during the removal process.
It is also vital for employers to ensure that known ignition sources such as machinery that emit open flames or sparks are not surrounded by potentially combustible dust. Similarly, electrical systems must be properly maintained so that electrical shorts don’t lead to combustion.
Employees responsible for removing dust must also be provided with personal protective equipment that does not generate sparks. They should also have cameras and other video recording equipment so that they can identify and mark potentially hazardous dust accumulations. These images and recordings can help employers identify deficiencies within the setup and operation of existing dust removal systems.