Takeaway
In short, this case upholds OSHA’s interim inclusion of combustible dust in its hazard-communication regime: adequate notice, established agency guidance, and workable compliance methods defeated the industry’s procedural, evidentiary, and facial-vagueness challenges.
OSHA’s Hazard Communication Standard requires manufacturers, importers, and employers to identify hazardous workplace chemicals and communicate their hazards through labels, safety data sheets, written programs, and employee training. In 2012, OSHA revised the Standard to align it with the international Globally Harmonized System for chemical classification and labeling.
The final rule expressly included “combustible dust” within the definition of a hazardous chemical. OSHA did not adopt a single definition in the rule’s text. Instead, it referred regulated parties to its Combustible Dust National Emphasis Program and other guidance while a separate, broader combustible-dust rulemaking remained pending. The rule affected agricultural businesses because grain dust can create fire and explosion hazards.
National Oilseed Processors Association and other petitioners, representing grain and agricultural-product businesses, petitioned the D.C. Circuit directly for review under the Occupational Safety and Health Act. They sought vacatur of the rule as applied to combustible grain dust, arguing inadequate notice, insufficient evidentiary support, and unconstitutional vagueness. There was no lower-court decision; the court of appeals denied the petition for review.
Issue #1
Whether OSHA gave adequate notice and an opportunity to comment before subjecting combustible grain dust to the revised Hazard Communication Standard.
Holding
Yes. The final treatment of combustible dust, including grain dust, was a logical outgrowth of OSHA’s proposal.
Reasoning
The proposed rule expressly stated that OSHA was considering treating combustible dust as an “unclassified hazard” subject to the Hazard Communication Standard’s labeling, safety-data-sheet, and training requirements. OSHA specifically asked commenters whether that approach would provide adequate interim coverage for combustible dust. That notice adequately alerted interested parties that combustible dust would be regulated under the Standard.
The grain industry also had substantial prior notice that OSHA regarded grain dust as covered. OSHA had long interpreted the Hazard Communication Standard to reach agricultural products that pose dust-explosion hazards, and in 1994 it specifically rejected the industry’s position that grain dust was outside the Standard. OSHA’s National Emphasis Program and 2009 guidance likewise identified agricultural materials, including flour, as potentially combustible dusts.
The final rule did not make an unforeseeable change by identifying combustible dust as a specific hazard rather than an unclassified one. In either formulation, combustible dust was to be treated as a hazardous chemical and subjected to the same core communication obligations. The proposal also alerted employers that they must consider hazards arising from downstream uses of their products.
Issue #2
Whether OSHA acted unreasonably or without substantial evidence by declining to include a single uniform definition of “combustible dust” in the final rule.
Holding
No. OSHA reasonably relied on an interim operative definition and guidance while related domestic and international work continued.
Reasoning
OSHA did not leave regulated parties without any definition. The final rule directed them to the National Emphasis Program’s operative definition: a combustible particulate solid that presents a fire or deflagration hazard when suspended in air or another oxidizing medium over a range of concentrations. OSHA also identified relevant industry consensus standards as additional guidance.
The court concluded that the different government and industry formulations were materially consistent. Each focused on particles capable of causing a fire or explosion under relevant conditions; their principal disagreement concerned whether and how to use a maximum particle size. The existing Grain Handling Standard itself referred to “combustible dust” without further defining it, and the record did not show that the grain industry had been unable to understand that term in practice.
OSHA adequately explained its policy choice. It considered immediate communication protections necessary because combustible-dust hazards were serious, because global work on a more precise definition was delayed, and because excluding dust from the Hazard Communication Standard would remove protections OSHA had long understood the Standard to provide. The separate combustible-dust rulemaking could address broader workplace-control measures, whereas this rule served the narrower function of transmitting hazard information.
Issue #3
Whether the petitioners’ facial due-process vagueness challenge was ripe for pre-enforcement review.
Holding
Yes. The challenge presented a sufficiently concrete legal dispute and the rule had already imposed practical burdens on petitioners’ members.
Reasoning
The claim was principally legal: petitioners argued that the absence of adequate notice about what counts as combustible dust invalidated the provision in all applications. Further factual development in a later enforcement proceeding would not materially improve the court’s ability to assess that facial argument.
The rule had already affected the industry. Its training provisions had become effective, and regulated businesses had to decide whether they needed to train workers and classify products as combustible dust, while risking enforcement if they guessed incorrectly. Those immediate compliance costs established hardship.
Pre-enforcement review was especially appropriate because the Occupational Safety and Health Act expressly authorizes direct review of OSHA standards within a sixty-day period. Delaying review could effectively deprive petitioners of their statutory opportunity to bring a pre-enforcement challenge.
Issue #4
Whether the final rule’s use of the term “combustible dust” was unconstitutionally vague on its face under the Due Process Clause.
Holding
No. The rule, read with OSHA’s publicly available guidance, gave regulated parties fair warning of the required classification and communication obligations.
Reasoning
Due process is satisfied when a regulated party acting in good faith can identify with ascertainable certainty the standards the agency expects it to meet by consulting the regulation and the agency’s public statements. The relevant question was therefore whether the term and OSHA’s instructions provided fair notice, not whether every conceivable factual application had already been resolved.
The term had an established regulatory context. The Grain Handling Standard already used “combustible dust” in defining fugitive grain dust, and petitioners had not shown that the term was unclear in that setting. The revised Hazard Communication Standard also clearly stated what employers must do once a combustible-dust hazard is identified: provide labels, safety data sheets, and training.
OSHA’s National Emphasis Program and 2013 guidance supplied workable methods of classification. Past explosion experience was a strong indication of a hazard; employers could also use laboratory data, published test results, or, if needed, particle-size measures. A grain-elevator operator with prior dust explosions, for example, would know that its materials presumptively presented a combustible-dust hazard absent evidence that the incident resulted from abnormal or unforeseeable conditions.
The availability of alternative reliable methods did not invite arbitrary enforcement. OSHA gave a hierarchy of useful evidence and allowed employers to use more protective particle-size standards. Although a particular employer might later raise an as-applied vagueness objection in an enforcement case, the provision was not invalid in all applications and therefore was not facially void for vagueness.