Friday, April 27, 2012

Understanding the WorkSafeBC Lakeland Mills inspection reports

Recently there has been extensive media coverage on the recently released WorkSafeBC Lakeland Mills inspection reports. Media accounts mention dust levels in the reports but fail to inform the public that the issue of dust was primarily respiratory health hazards of dust and not fire and explosion hazards of dust. There is a big difference. In many instances airborne levels of combustible dust can be indicative of engineering control measures such as local exhaust ventilation is not adequate or insufficient housekeeping.

Excerpts from Lakeland Mill Report

 

This inspection report focused on the MSI, Noise and Wood dust components of the provincial high risk strategy.

2/3/2009 page 33 Most processing saws and chipping heads are equipped with local exhaust ventilation, which appear to reduce accumulations of fine dust. No recent monitoring of exposure to wood dust has been conducted. Wood dust exposure will be further evaluated during subsequent inspections.  This is an item that should be re-evaluated due to the changes in productivity that has occurred over recent years and the fact the majority of the wood being processed is dry beetle killed pine

 
SRO/OHO Barry Nakahara and I inspected this worksite as part of the high risk provincial strategy

5/27/2010 page 67 We confirmed that hearing tests are being done regularly. We discussed potential dust exposure and the need for appropriate respiratory protection for workers performing clean up of dusty areas. The employer has recently conducted air monitoring for dust and exposures relating to the end-spraying operation. These results were reviewed and no significant problems were noted.

 
OSO Darren Beattie and I conducted an inspection of this jobsite on February 6, 2012 to assess compliance with the Workers' Compensation Act and the Occupational Health & Safety Regulation. A separate inspection report will be issued by OSO Beattie summarizing his observations.

2/9/2012 Page 112 We discussed the wood dust observed throughout the mill. At the time of inspection, the airborne concentration appears to be below the exposure limit (Non-allergenic wood dust EL = 2.5 mg/m3) in the work areas visited.  There are accumulations of piles of wood dust in various areas of the mill. We reviewed the requirement to prevent the accumulation of hazardous amounts of wood dust.

Resource
Lakeland Mills inspection reports

Guidance WorkSafeBC Directive Order to Sawmill Employers

Now that the topic of workplace combustible fire and explosion hazards is out the open in British Columbia  sawmills it is important for facility owners and managers to understand the steps in a risk assessment in developing engineering and administrative control measures. The missing link that has not been communicated to stakeholders is the importance of understanding the BC Fire Code which references NFPA 664 Standard for the Prevention of Fires and. Explosions in Wood Processing and Woodworking. Facilities. An excellent resource in understanding NFPA 664 is the 24 page .pdf document developed by the  Wood Machinery Manufactures of America (WMMA).


The BC Fire Code references NFPA 664 Standard for the Prevention of Fires and. Explosions in Wood Processing and Woodworking. Facilities. For example,  BC Fire Code (1998), Hazardous Processes & Operations (page 113 .pdf) Section Part 5.3. – Dust Producing Processes (page 115 .pdf)

Many don't realize that it is not WorkSafeBC which enforces the BC Fire Code but instead the Fire Commissioner ("Office") and the Office's jurisdiction over fire safety and fire protection in British Columbia. The Office is the senior authority having jurisdiction over fire safety and prevention in B.C. The Office administers the Fire Services Act and it regulations, and appoints and trains local assistants to the Fire Commissioner.

"where WorkSafeBC prevention officers observe what they believe to be a violation of the Fire Services Act or its regulations, prevention officers will notify the local assistant to the Fire Commissioner."


Solely relying on the WorkSafeBC regulation on combustible dust is not sufficient in undertaking a comprehensive risk assessment in addition to developing a combustible dust control program. An understanding of NFPA 664 as referenced in the BC Fire Code will assist immensely in conducting a safety review for combustible dust in sawmills.

To assist stakeholders WorkSafeBC published OHS Guideline G5.81 Combustible Dust-Sawmill Facilities (April 25, 2012) The recent guideline provides information on a Combustible Dust Program which includes elements of hazard mitigation; facility risk assessment, written combustible dust control program, and a hazardous communication program.

Update April 28, 2012 WorksafeBC Bulletin — Clean-up of hazardous combustible dust
"WorkSafeBC has prepared a simple one-page bulletin in safe cleaning procedures of combustible dust that  protect workers."

Resources 
WorkSafeBC Directive Order to Sawmill Employers 
NFPA 664 Combustible Dusts – Overview (WMMA)
BC Fire Code (1998)
OHS Guideline Combustible Dust Sawmills

Relying on housekeeping as a first line of defense against explosion and fire is a false economy

Why going cheap on the dust collection & control system is short sighted...

We all know that our cars and trucks have air and oil filters to catch dust to avoid abrasive wear of the engine. We have seen news articles about how airborne dust is not good for jet engines - like when that Icelandic volcano erupted in 2010, or the Argentinean eruption in 2011.

So, why do so many industrial operations let their dust collection systems get plugged up and fail to perform? Assuming that they bother to install adequate dust controls in the first place?

One common complaint from the people who run foundries and factories is cost - buying a dust control system costs some serious coin, and too many operations try to go bottom dollar when they buy equipment. 

Another issue is maintaining and cleaning the equipment - this requires technicians with some training, whereas handing a laborer a shovel or a broom is a good way to keep him busy when things are a bit slow for making product.


This is especially problematic when the dust in question is combustible.

I've lost track of the mills and factories I've consulted for who have had "snowdrifts" of dust piled up because they didn't have the right dust collection and control system, and instead relying on housekeeping to deal with the mess.

 Fortunately, most of these operations were making steel or cement, and slag and rock dust don't burn or explode. They are abrasive however, and the dusts stick to exposed lubricated parts, like the cables of the hoist of an overhead crane, or the packing of a pillow-block bearing.

 It's difficult to quantify how much service life get eaten up by the grit grinding away on the machinery, but a knowledgeable maintenance superintendent can do predictive maintenance for his/her own shop, and develop the trend data.

Things get more complicated when the dust has hazardous qualities, such as toxicity or flammability.

OSHA has a distinct preference for engineering controls of such dusts - it makes sense to control and confine the potential hazard, making the work environment safer.

When we look at some key fatal accidents, we find that the dust control systems were no longer working as designed or installed.

The Hayes Lemmerz explosion in Huntington, IN in 2003 was largely due to the inadequacy of their dust collection system  which was leaking aluminum powder from its ductwork.

 The rash of explosions and fires at Hoeganaes in Gallatin, TN in 2011 were exacerbated by the prevalence of combustible iron powder due to the lack of adequate function of the ageing dust control equipment.

   The Imperial Sugar explosion in Port Wentworth, GA in 2008 was also largely due to inadequate dust controls. 

When we look at the accident investigation photographs from these incidents, the prevalence of fugitive dust (dust which has escaped containment) is obvious - and frightening to a knowledgeable observer.

Housekeeping presents several problems as a means to control combustible dust. A major problem is that dust will deposit on any horizontal surface - like roof beams, conduits, and the top surfaces of machinery and internal enclosures (electrical & machinery rooms for example).

Then there is the issue of just how one goes about cleaning up the accumulated fugitive dusts. The CSB report on the explosion and fire at CTA Acoustics in Corbin, KY in February of 2003 shows that sweeping and blowing combustible dust can easily generate a combustible cloud, which can react with any ignition source.

Conventional industrial vacuum cleaners ("Shop Vacs") are not much better, since they lack specific grounding and venting to prevent internal explosion of the dust which they are sweeping up.

The recent sawmill explosions in British Columbia in January and February would appear to also be due to fugitive dust (final reports from the BC government are not yet available). The news reports indicate that the mills were operating with reduced staff, which would indicate that there were fewer employees available for maintenance and housekeeping.

Factor in a drier source of timber - beetle killed trees - and the possibilities for dust problems become all too real.


The destructive fire at the Swany White flour mill in Minnesota in December of 2011 appears to be another example of fugitive dust catching fire - possibly due to a hot bearing on the ~100 year old milling and sifting equipment.

So, relying on housekeeping as a first line of defense against explosion and fire is a false economy - not only is there a greater risk to the workers workers, but the maintenance costs for machinery are higher, due to increased abrasion from dust getting into the moving parts of machinery.


Eric Anderson
Contributed by Eric Anderson
Vice President
Renewable Energy Technologies, Inc.
eanderson@eandersonventilation.com

 

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