NASHVILLE, TN -- Two flash fires at Hoeganaes Corporation plant in Gallatin, TN, including one which killed an employee, were fueled by combustible metal dust, according to test results released by the U.S. Chemical Safety Board (CSB).
 
The CSB said the tests confirmed the preliminary conclusions that the iron powder had accumulated throughout the facility and became airborne in combustible concentrations. A flash fire on January 31 killed one worker and seriously burned another. A similar fire occurred at the plant, which manufactures "atomized" iron powder used for auto parts and other metal products, on March 29 and caused one injury.

In the fatal fire, two mechanics were standing alone on an elevated platform near the top of the bucket elevator, which had been shut down and was out of service until maintenance personnel could inspect it. When the bucket elevator was restarted the movement immediately lofted combustible iron dust into the air. The dust ignited and the flames engulfed the workers causing their injuries. A dust collector associated with the elevator was reported to have been out of service for the two days leading to the incident.

The second incident occurred less than two months later on March 29 when a plant engineer, who was replacing igniters on a furnace, was engulfed in combustible dust which ignited. In the course of the furnace work, he inadvertently dislodged iron dust which had accumulated on elevated surfaces near the furnace. He experienced serious burns and bruises as a result of this second event; a contractor witnessed the fireball but escaped without injury.

In the course of reviewing company documents, the CSB found that last year Hoeganaes submitted 23 dust samples from the Gallatin facility to an independent laboratory for testing and 14 were found to be combustible. Furthermore, investigators found that the facility had documented multiple reports of flash fires during repairs on furnace belts at their facility located in Cinnaminson, N, which resulted in two injuries in 2000 and one fatality in 1996.

The CSB continuing investigation will examine the company’s dust prevention efforts at the facility and its compliance with the National Fire Protection Association Standard 484 that details requirements for dust collection systems, dust cleaning frequency, and building construction and egress provisions.

In 2006 the CSB completed a study of combustible dust fires and explosions, which identified 281 incidents that occurred from 1980 to 2005, killing 119 workers and injuring more than 700. The study findings resulted in a recommendation to the U.S. Occupational Safety and Health Administration (OSHA) to develop a standard that comprehensively addresses combustible dust explosions, including wood dust. In 2009, OSHA agreed to develop a combustible dust standard. OSHA is currently in the early stages of the rulemaking process for the standard.

Read more about U.S. Chemical Safety Board's findings on Hoeganaes Corporation's ComDust fires.

Posted by Rich Christianson

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