OSHA Fines Plant Rocked By Dust Collection System Fire And Explosion
OSHA has issued huge fines over a combustible dust fire and explosion the tore through a wood pellet manufacturer’s dust collection systemMay 14, 2012 | Jaffrey, NH -- OSHA fined the New England Wood Pellet, LLC a total of $147,000 over safety violations after a combustible dust fire and explosion rocked the company’s plant in Jaffrey, NH last week. The fines, which are some of the biggest yet this year, and the accompanying report on the incident that criticizes the company for failing to “effectively minimize and address clearly recognized hazards that could kill or disable workers in a catastrophic incident.”
The company for its part has fired back, saying OSHA’s findings are “one-sided and unfairly dismissive of the company's past and ongoing efforts to improve worker safety at its Jaffrey facility.”
The October 20, 2011 fire and explosion started when combustible wood pellet dust from the facility caught fire while in the plant’s dust conveyor system. After the fire started in the wood pellet cooler, the dust collection/conveyor system then transported the now burning dust throughout the system to equipment in other parts of the facility. Once it reached the dust collector itself, the embers caused an explosion that then further spread the fire into storage silos that were located adjacent to the dust collector. The explosion also caused large amount of combustible dusts that had accumulated throughout the facility on overhead rafters and on other elevated places to catch fire.
Eventually, the fire became so large that it took more than 100 firefighters from 14 departments to control the blaze and took about 14 hours to extinguish.
The plant, which manufactures wood pellets by compressing wood dust, was previously cited by OSHA for a lack of properly installed and operated dust collection systems in the facility and for insufficiant housekeeping measures to control the accumulation of the combustible wood dust throughout the facility. For this reason, several of the citations from the October 20th incident were registered as “repeat serious offenses” that increased the fines considerably.
Specific Violations: Poor Dust Collection System Design, No Explosion Prevention/Protection
During its investigation OSHA found that a number of factors contributed to the severity of the incident. It found that the plant had failed to properly design and prepare their dust collection system for the fire and explosion hazards created by the combustible nature of the wood pellet dust. The report cited several instances where the dust collection/conveyor system, specifically the ductwork, pellet cooler, and the dust collector (baghouse) was either completely lacking any sort of fire suppression and explosion protection devices or were improperly installed.
Ductwork between various equipment located in different parts of the plant had no fire suppression devices (such as spark arrestors, ember suppression systems, etc.) to prevent sparks and embers from spreading throughout the system. This lead to a conflagration in the pellet cooler spreading through the ductwork to the dust collector in another part of the plant. Once in the dust collector, the fire lead to a dust explosion. While the dust collector did have explosion protection, it was not adequately sized, properly designed in that the explosion relief vents were positioned so as to vent the explosion back into the building towards workers in the area and out onto adjacent storage silos then subsequently caught fire.
The explosion also propagated back through the ductwork, which then burst open igniting large accumulations of dust on overhead rafters and other facility machinery.
OSHA also faulted the plant with failing to design and build ductwork and the dust collector to sufficient strength to withstand the maximum foreseeable explosion pressures from a potential combustible dust explosion. This lead to among other things, the door of the dust collector being blown off the collector, becoming a missile hazard. Since the dust collector and ductwork were of inadequate strength to withstand a potential explosion, OSHA faulted the company for placing the dust collector inside the building.
Additionally, OSHA cited the plant for poor housekeeping efforts, failing to control the accumulation of the combustible wood pellet dust on overhead spaces such as rafters and large equipment. The company had a policy of cleaning dust accumulations using compressed air, in direct violation of OSHA regulations, for which is was fined previously. The large build up of combustible dust throughout the facility lead to secondary dust fires and explosions.*
In response to OSHA’s report, the company has defended itself, claiming it had taken all reasonable steps to ensure the safety of its workers. “Since 2008, New England Wood Pellet has worked cooperatively with [OSHA’s representatives], retained engineers and consultants, and spent over $2 million on various improvements to enhance worker safety at its Jaffrey facility” a statement from the company read.
They also took issue with comments from OSHA’s area director for New Hampshire, Rosemarie Ohar, and said they look forward to sharing their thoughts with OSHA regarding the citations. “We have a cooperative relationship with the New Hampshire OSHA office. This is the first time we'll get to share with them what we think since this citation was issued. We'll discuss the content of the citation and the amount of the penalties, and hopefully we can come to agreement there and continue to work together to make improvements in our plants, which we plan on doing anyway.”
Lesson For Others
Whether the company is successful in overturning or reducing the issued fines, this incident demonstrates the importance of proper dust collection system design in preventing combustible dust fires and explosions. Lack of effective planing and engineering in the system, as well as overlooking the seriousness of the threat combustible dusts pose lead to extensive damage to the plant, and large fines from OSHA.
While the company may be able to afford the fines, downtime from the resulting damage to the plant, and the now extensive repair costs will no doubt cost the company far more than remedying the problem in the beginning would have been.
About The Author:
Dominick DalSanto is an Author and Environmental Technologies Expert, specializing in dust collection systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Marketing Director and Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs. Follow Dominick on Google+
* A secondary dust fire/explosion occurs when an initial explosion causes a shockwave that then dislodges and disperses accumulations of dust often in elevated locations. The resulting dispersal of dust into the air many times leads to explosions of far great magnitude and destructive power than the initial conflagration.
Additional Information About Combustible Dust Hazards:
Nine Years After Deadly Dust Explosion and Still No Comprehensive Dust Standard - CSB Director calls upon OSHA to finalize its long awaited combustible dust rule.
The Potential For Dust Explosions In Dust Collection Systems A guide to combustible dust hazards in general industry and how to minimize them.