Boom! The dangers of wood dust

Sam Tom was returning from a coffee break in January 2012 at the Babine Forest Products sawmill in Burns Lake, B.C. when he saw a flash.

A moment later: «Boom. Everything just went flying,” Tom later told the Canadian Press wire service.

The explosion and resulting fire wrecked the mill, killing two and injuring 20. The likely cause, according to a report released in May by the British Columbia Safety Authority, was improperly managed wood dust, possibly ignited by an electrical panel, high-watt light bulb or earlier fire.

The incident was the latest in a series of explosions and conflagrations in the United States and Canada during the last five years caused or suspected to have been caused by combustible wood dust.

They include the April 2012 disaster at another British Columbia saw mill, this one in Prince George, that sent flames nearly 200 feet into the air, killing two and injuring 22; a large 2011 fire at a New Hampshire wood pellet factory; and a 2008 explosion at an Imperial Sugar mill in Georgia that left 13 dead and dozens injured.

These catastrophes reinforced what has long been known in the woodworking industry: Combustible wood dust and a spark spell disaster.

Since the Imperial Sugar refinery catastrophe, in which wood dust stirred up by the initial sugar dust blast is believed to have caused a secondary explosion, both the Occupational Safety and Health Administration and the National Fire Protection Association have revisited wood dust regulations.

In 2008, OSHA increased dust inspections and in 2009 announced it would begin development of a federal standard for industrial dust. The agency began writing its first regulation governing wood dust. Years later, that regulation has yet to reach the draft stage.

The fire protection association, meanwhile, published an updated preliminary standard for combustible dust earlier this year, the first stage in consolidating the fundamental requirements into a single standard. The organization will preserve standards for specific types of Boom! The dangers of wood dust Sam Tom was returning from a coffee break in January 2012 at the Babine Forest Products sawmill in Burns Lake, B.C. when he saw a flash.

A moment later: «Boom. Everything just went flying,” Tom later told the Canadian Press wire service.

The explosion and resulting fire wrecked the mill, killing two and injuring 20. The likely cause, according to a report released in May by the British Columbia Safety Authority, was improperly managed wood dust, possibly ignited by an electrical panel, high-watt light bulb or earlier fire.

The incident was the latest in a series of explosions and conflagrations in the United States and Canada during the last five years caused or suspected to have been caused by combustible wood dust.

They include the April 2012 disaster at another British Columbia saw mill, this one in Prince George, that sent flames nearly 200 feet into the air, killing two and injuring 22; a large 2011 fire at a New Hampshire wood pellet factory; and a 2008 explosion at an Imperial Sugar mill in Georgia that left 13 dead and dozens injured.

These catastrophes reinforced what has long been known in the woodworking industry: Combustible wood dust and a spark spell disaster.

Since the Imperial Sugar refinery catastrophe, in which wood dust stirred up by the initial sugar dust blast is believed to have caused a secondary explosion, both the Occupational Safety and Health Administration and the National Fire Protection Association have revisited wood dust regulations.

In 2008, OSHA increased dust inspections and in 2009 announced it would begin development of a federal standard for industrial dust. The agency began writing its first regulation governing wood dust. Years later, that regulation has yet to reach the draft stage.

The fire protection association, meanwhile, published an updated preliminary standard for combustible dust earlier this year, the first stage in consolidating the fundamental requirements into a single standard. The organization will preserve standards for specific types of much dust,” Scott says.

Being able to write your name in the dust is another danger sign, he says.

In addition, ductwork should be round instead of square to prevent dust buildup, he says.

Cleaning up wood dust is not as simple as turning on a blower. OSHA has cited shops that fail to use specialized and expensive vacuum cleaners that don’t emit a spark to clean up wood dust, Scott says.

Minimizing the possibility of sparks is another key element in protecting against wood dust explosions, Scott says. All fires require three things: burnable material, air and an ignition source, he notes.

Potential ignition sources — such as electrical equipment — need to be carefully managed and kept away from areas where fugitive dust could gather, Scott says. Shops should be designed to contain any conflagration should it occur, he says.

Plastic piping, because it’s prone to static electricity, is another potential danger, he says.

«Having says that, having a clean shop is always the best line of defense,” Scott says. «Proper housekeeping to eliminate fugitive dust and finding out where it’s coming from are keys.”

State of regulation

Regulation of industrial dust is nothing new, says Guy Colonna, a National Fire Protection Association division manager. His organization, which sets standards for local fire and safety officials, issued its first wood dust guidelines in 1930, he says.

A greater focus on combustible dust began in the mid-2000s after three incidents in 2003, Colonna says. The Chemical Safety Board conducted a study that identified 281 incidents, about 10 a year, in a variety of industries from 1980 to 2005, he says.

«Consequently, the Chemical Safety Board concluded this is a regular event and therefore there needed to be more attention paid to it,” Colonna says.

The Imperial Sugar explosion in 2008 only added to the concern, helping prompt OSHA to increase industrial dust inspections, Colonna says.

The fire protection association, meanwhile, has five industrial dust standards for different materials, including one for wood dust, Colonna says. Since 2010, the organization has been working on a new industrial dust standard that brings the fundamental requirements into a single document, he says. In addition, the fire protection association will keep its existing standards for wood dust and other materials, he says.

The fire protection association will likely not include major changes to the wood dust standard, Colonna says.

«We are attempting to be proactive in making sure the NFPA documents remain a good resource to industries subject to OSHA,” Colonna says.

With a preliminary standard out, the fire protection association will issue a draft by September and a final standard by early 2014, Colonna says. It will then go into effect later that year, he says.

The fire protection association’s intention is also not only to update and strengthen its standard, but also to provide a model for possible future OSHA dust regulation, Colonna says.

OSHA has worked on a possible wood dust regulation since 2009, but has yet to issue a preliminary draft, Colonna says.

Greater OSHA scrutiny

Philip Bibeau, executive director of the Wood Products Manufacturers Association, says that his organization’s members have faced heightened OSHA scrutiny over wood dust for the last four to five years.

OHSA has visited numerous members of his organization, which typically have fewer than 50 employees, not based on complaints, but a list compiled by the agency, Bibeau says. Many have been cited, he says.

The inspections are placing an added burden on small wood shops already concerned about the impact of the Affordable Care Act and other issues, he says.

«The maximum thickness of dust on a flat surface is 1/32nd of an inch,” Bibeau says of OSHA inspectors. «They use a standard paper clip. If it’s thicker, that’s too much dust.”

But that standard may be too stringent. Colonna says that the fire protection association’s general dust standard is 1/32nd of an inch, but 1/8th of an inch for typical wood dust. That’s because wood dust is less dense than other types of industrial dust, he says.

Other wood industry trade groups reported no increased OSHA scrutiny over wood dust in recent years.

While they agreed that wood dust is a significant safety concern, some questioned whether the dangers were being overblown. They also questioned the need for federal regulation.

«The long and the short of it is, I think it’s better left to local authorities versus handing it down to the feds,” says Dave Grulke, executive director of the Cabinet Makers Association.

Gary Heroux, vice president of product acceptance at the Composite Panel Association, says that insurers also ensure compliance with wood dust safety requirements. Companies also often bring in independent experts to assure their operations are safe, he says.

«It seems like the standards in place today are working well for our industry,” Heroux says.

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