CSB Renews Push for OSHA Combustible Dust Standard After Fatal Mill Explosion
CSB Renews Push for OSHA Combustible Dust Standard After Fatal Mill Explosion
What Happened
The U.S. Chemical Safety Board has renewed its longstanding recommendation that OSHA develop a comprehensive standard specifically addressing combustible dust hazards. The agency released a new safety video revisiting the May 2017 explosion and fire at Didion Milling, a dry corn milling facility in Cambria, Wisconsin, that killed five workers and injured 15 others.
CSB board member Sylvia Johnson said “robust regulation” is needed to prevent these types of explosions, noting that OSHA has not yet started rulemaking on a general industry combustible dust standard despite years of CSB recommendations.
Why It Matters for Chemical Facilities
Combustible dust explosions remain one of the most underappreciated hazards in industrial settings. Without a dedicated OSHA standard, facilities that handle fine powders, dry chemicals, and granular materials must piece together compliance from general duty clauses, NFPA guidelines, and scattered industry-specific rules.
This patchwork approach leaves gaps. EHS managers at chemical warehouses, food processing plants, pharmaceutical facilities, and manufacturing sites often lack clear, enforceable benchmarks for dust collection, housekeeping, ignition source control, and explosion mitigation.
Key Details: The Didion Milling Disaster
The CSB's renewed push centers on the 2017 Didion Milling incident:
- 5 workers killed and 15 injured in a combustible dust explosion at a corn milling facility in Cambria, Wisconsin
- The explosion involved accumulated corn dust that ignited in the facility's processing areas
- CSB investigators found that inadequate dust control and housekeeping contributed to the severity of the blast
- The company had operated without a comprehensive combustible dust management program
The CSB has recommended a combustible dust standard multiple times since its 2006 study of the problem, but OSHA has not advanced a rulemaking. The National Fire Protection Association (NFPA) standards 652 and 654 provide guidance, but these are voluntary unless adopted by a local authority having jurisdiction.
What Chemical Handlers Should Watch For
Even without a new OSHA standard, facilities handling powdered or granulated chemicals should take several steps now:
- Conduct a dust hazard analysis (DHA) per NFPA 652 — most facilities were required to complete one by September 2020
- Review housekeeping protocols to prevent dust accumulation on surfaces, beams, and equipment
- Audit dust collection systems including filters, ductwork, and explosion venting
- Check SDS documentation for all powdered products to confirm dust explosion data (Kst values, minimum ignition energy)
- Train employees on combustible dust hazards and emergency procedures
If OSHA eventually issues a standard, facilities with documented DHAs and active dust management programs will be well-positioned for compliance.
Alliance's Take
Combustible dust risk is present wherever fine powders and dry chemicals are stored, handled, or processed. This includes many of the industrial and laboratory chemicals that Alliance Chemical supplies daily — from powdered acids and bases to granular water treatment compounds. The CSB's renewed focus on this hazard reinforces why proper documentation and hazard communication matter so much.
Every chemical we ship includes a complete Safety Data Sheet with relevant dust explosion data, flammability classifications, and recommended handling procedures. For powdered products, the SDS will specify Kst values, minimum ignition energy, and appropriate dust control measures where applicable. Our Certificates of Analysis confirm the physical form and particle characteristics of each lot.
If you are conducting a dust hazard analysis or updating your chemical inventory documentation, our team can help. Contact us at sales@alliancechemical.com for current SDS documents, product specifications, or to discuss your facility's chemical supply needs.
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