The Danger of Combustible Dust
Posted by
Justin RogersAugust 01, 2008 9:00 AM
On May 1, 2008, the United States House of Representatives passed H.R. 5522 . This bill requires the Secretary of Labor, Elaine Chao , to issue occupational safety and health standards regarding worker exposure to combustible dust.
There have been a number of deaths as a result of dust explosions within general industry, and according to the text of the bill, the Occupational Safety and Health Administration has failed to address this issue.
On June 8, 2008, this issue was discussed on 60 Minutes where Ed Foulke , the Assistant Secretary of Labor for Occupational Safety and Health, was interviewed. According to the interview, there are approximately 30,000 factories and plants at risk of a dust explosion, about 300 or more of which will be inspected by OSHA within the next year. However, where factories are inspected at the rate of 300 per year it will take around 100 years to have all 30,000 inspected. Another alarming statistic is that, “of 67 factories hit by dust explosions, only one of them was cited for a dust hazard by OSHA inspectors before the blast.”
A vast array of dust particles can be combustible. Dust from products that seem harmless such as sugar, tea, apples, cotton, tomatoes, and even peaches can be deadly if ignited. Agricultural dusts, carbonaceous dusts, chemical dusts, metal dusts, and plastic dusts are all listed by OSHA as products that could potentially cause a combustible dust explosion .
A typical fire is caused by a combination of three factors: oxygen, heat, and fuel. A dust explosion occurs when oxygen, heat, and fuel are present along with dispersion of a sufficient quantity and concentration of dust particles confined to a particular area. What happens during a dust explosion is some initial or primary explosion occurs that then triggers the ignition of dust dispersed in the air. These second explosions are more violent and destructive than the primary explosions.
In order to help prevent dust explosions, OSHA has listed recommendations for dust and ignition control such as minimizing the escape of dust from process equipment, using surfaces that minimize dust accumulation and facilitate cleaning, controlling static electricity, and controlling smoking, open flames, and sparks.