Good housekeeping practices not only help to maintain clean work areas, but in some cases, may prevent potential catastrophes. In 2008, we were witnesses of the dangers of combustible dust with the explosion at the Imperial Sugar refinery in Georgia where 14 employees were killed and 42 were injured. But this is not a new hazard. The first recorded combustible dust explosion dates back to December 14, 1785 at a flour warehouse in Italy. A worker was using a shovel to transfer flour and a lighted lamp to work by.(1) All the necessary elements for a combustible dust explosion were present:
- Heat: The lighted lamp and/or possibly electrostatic charges due to the dry season.
- Fuel: Flour and other agricultural dust/products are combustible dusts.
- Dispersion: Flour was likely suspended in the air during the transfer.
- Confinement: The warehouse structure confined the cloud of suspended combustible dust.
It’s not just agricultural products/dust that can be classified as combustible dust but also plastic dusts, chemical dusts, metal dusts and carbonaceous dusts. Recent explosions relating to metal dust occurred in 2010 at a titanium plant in West Virginia killing 3 employees, and in 2011 at a metal powders facility in Tennessee where 5 employees were killed. In 2012, a combustible dust explosion occurred at an ink plant in New Jersey where 7 employees were injured.
As of October 2014, there is no OSHA standard addressing combustible dust, but it is a known occupational hazard in which a compliance officer can cite under Section 5(a)(1) under the OSH Act. OSHA is, however, developing a standard. It should be noted that it is at the early stages, still a long way to go before it becomes a law--if it survives the rulemaking process.
The National Fire Protection Association has published a series of standards for the prevention of fire and dust explosions and they can be viewed for free through the association’s website. The series of standards include:
- NFPA 61: Standard for the Prevention of Fires and Explosions in Agricultural and Food Processing Facilities
- NFPA 484: Standard for Combustible Metals
- NFPA 654: Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids
- NFPA 655: Standard for Prevention of Sulfur Fires and Explosions
- NFPA 664: Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities
For more information about combustible dust and how it can be identified and controlled, visit the OSHA website or The US Chemical Safety Board. MEMIC policyholders can watch a webinar on combustible dust at MEMIC Safety Director. The US Chemical Safety Board has developed videos detailing the causes of the explosions they have investigated including an educational video entitled, Combustible Dust: An Insidious Hazard:
(1) RK Eckhoff. (2003). Dust explosions in the process industries, Third Edition: Identification, Assessment and Control of Dust Hazards. Burlington, MA: Gulf Professional Publishing.