OSHA Issues Guidance on Combustible Dust Hazards Under New HazCom Rule

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By Robert Iafolla

Jan. 2 — When chemical manufacturers and importers lack direct experience with the combustible dust hazards of products they're shipping, they should use laboratory testing, published test results or particle size to classify them under the new hazard communication standard, according to an Occupational Safety and Health Administration memo released Dec. 31.

Manufacturers and importers are responsible for considering the combustible dust hazards of the chemical in the form they're shipped as well as those that might stem from normal use and foreseeable emergencies, OSHA said in its memo.

OSHA's standard interpretation memo is designed to guide agency inspectors in deciding whether products are classified properly for combustible dust hazards. The guidance is for inspections of manufacturers and importers, typically from referrals regarding faulty labels or safety data sheets, rather than for inspection of downstream users. Companies must comply with most provisions of the rule by June 2015.

Guidance Amid Uncertainty

The standard's handling of combustible dust has emerged as an area of great concern for industry, with some advocates claiming that the agency engaged in backdoor rulemaking by including combustible dust in the hazard communication rule. The regulation's treatment of combustible dust is the subject of an ongoing legal challenge in a federal appeals court.

The standard itself doesn't define combustible dust, pointing to ongoing OSHA rulemaking and efforts at the United Nations as a reason for that absence. Instead, the rule cited existing guidance on combustible dust, such as the agency's national emphasis program on the substance.

Given that uncertainty, the memo should be useful to companies by providing several different approaches for classifying a substance's combustible dust hazard, Daniel Levine, president of Product Safety Solutions, told Bloomberg BNA Jan. 2.

The material in the memo is consistent with previous combustible dust information published by OSHA, said John Howell, vice president of GHS Resources Inc.

“However, it might give some classifiers heartaches who hadn't previously thought about the issue and need, now more than ever, to consider whether their product might be a combustible dust under foreseeable emergencies,” Howell told Bloomberg BNA Jan. 2.

Direct Knowledge, Alternatives

If a company knows that a product has been involved in a dust fire or explosion, the OSHA memo said, then it should classify the product as a combustible dust. The exception is if the company can show the conditions around the dust event didn't arise from expected use of the product or foreseeable emergencies.

Absent direct knowledge, the memo provides three other approaches that shippers can use to classify combustible dust hazards: laboratory tests, published results and particle size.

The OSHA memo pointed to testing methods described in ASTM International standards for establishing whether a material poses a combustible dust hazard.

In addition, the memo cited lists of test results for various materials published by the National Fire Protection Association, and includes online links to its own list and a database maintained by the Institute for Occupational Safety and Health of the German Social Accident Insurance system.

De Facto Definition?

Companies can use test data for similar materials if there isn't any data available for the substance that they are trying to classify for dust hazards, the memo said. Classification based on dust particle size—borrowed loosely from the consensus standard NFPA 6549—can be used when there is no test data or if the testing is inconclusive, the memo said. The memo appears to provide a de facto definition of combustible dust.

“If the material will burn and contains a sufficient concentration of particles 420 microns or smaller to create a fire or deflagration hazard, it should be classified as a combustible dust,” the memo said.

In a nod to more recent consensus standards, the memo said companies can use 500 microns as a threshold particle size.

Perpetuating a Problem

Marc Freedman, the U.S. Chamber of Commerce's executive director of labor law policy, said the memo perpetuates the problems that OSHA created by including combustible dust in the standard. Freedman told Bloomberg BNA Jan. 6 that the agency didn't allow for full stakeholder comment on that topic during the rulemaking process, which is especially problematic given that even defining combustible dust is a complex and contentious issue.

“At the end of the day, OSHA still doesn't have a definition of combustible dust, and employers are still expected to identify combustible dust hazards and train their employees accordingly,” Freedman said. “That's not appropriate. The way the memo reads, it is effectively implementing a non-OSHA, consensus organization's definition without the benefit of rulemaking, without a feasibility analysis, economic analysis or examination of its effect on small business. That's not how it's supposed to be done.”

Downstream Processing

Freedman also took issue with the memo's explanation of a shipper's responsibility for predicting combustible dust hazards that could arise downstream after shipping, from normal use and foreseeable emergencies.

“ ‘Foreseeable emergencies'—that's a contradiction in terms,” he said. “An emergency by definition is not foreseeable.”

The consideration of combustible dust hazards arising from downstream processing is the area of the new hazard communication standard that people are struggling with the most, said Denese Deeds, senior consultant at Industrial Health & Safety Consultants Inc. It can be especially challenging for organic compounds like plastics, foods and wood that are not hazardous in the form that they're shipped in, but could generate combustible dust once they're processed, she told Bloomberg BNA Jan. 6.

Deeds said that although the OSHA memo doesn't directly address it, there doesn't seem to be anything preventing a company from adding further explanation in the body of the safety data sheet saying that the combustible dust is generated during processing.

“It does seem odd to look at a solid material and think that you're looking at a combustible dust hazard,” Deeds said.

To contact the reporter on this story: Robert Iafolla in Washington at riafolla@bna.com

To contact the editor responsible for this story: Jim Stimson at jstimson@bna.com

The OSHA memo on classifying combustible dust hazards is available at http://tinyurl.com/lpyod9n.