“I will show you fear in a handful of dust.”  — T.S. Elliot

OSHA does not have a combustible dust regulation.

Instead, it relies on a hodge-podge of regulations combined with the General Duty Clause. If someone wants to understand what OSHA expects in terms of combustible dusts, they must turn to OSHA’s Combustible Dust National Emphasis Program, CPL 03-00-008.

OSHA issued the original version of this compliance directive for OSHA inspectors in October 2007, but quickly revised it after the explosion at the Imperial Sugar Company in Port Wentworth, Georgia on February 7, 2008. The reissued version of CPL 03-00-008 came out just one month later, on March 11, 2008.

After the March 11, 2008, version came out so quickly, there was high hope that OSHA would develop a comprehensive combustible dust regulation. Now, fifteen years later, on January 30, 2023, OSHA has revised and issued a third version of the Combustible Dust NEP. It’s still not a comprehensive combustible dust regulation, but it does represent OSHA’s current thinking on combustible dusts.

So, What’s New?

Despite news releases and associated fanfare, there is not much new about the new NEP. The program is now permanent; the new CPL 03-00-008 is “active until further notice.” The previous version had seven appendices, while the new version only keeps three of them. The four absent appendices—B, E, F, and G—are not gone, however. They are in the OSHA Technical Manual chapter on combustible dusts. The remaining three appendices are now Appendices A, B, and C, all of which are revised.

Appendix A:  NFPA Standards/Publications and FM Global Datasheets

Appendix A is an updated list of relevant standards from NFPA, FM Global Datasheets, and a few books published by the Center for Chemical Process Safety (CCPS). These documents are informative and will help a facility be safer, but they have not been incorporated by reference into OSHA regulations, so are not enforceable by OSHA.

The list in Appendix A will soon be out-of-date. OSHA lists 17 NFPA standards as relevant to combustible dusts. However, NFPA has undertaken an initiative to consolidate all of its combustible dust hazards, achieving something that OSHA has been unable to do.

Sometime in 2024, NFPA will be issuing NFPA 660, Standard for Combustible Dusts. It will consolidate six of the NFPA standards on OSHA’s Appendix A list:

  • NFPA 61 Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities
  • NFPA 484 Standard for Combustible Metals
  • NFPA 652 Standard on the Fundamentals of Combustible Dust
  • NFPA 654 Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids
  • NFPA 655 Standard for Prevention of Sulfur Fires and Explosions
  • NFPA 664 Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities

A feature of these standards, and of the upcoming consolidated standard, is a requirement to perform a Dust Hazard Analysis, a DHA. While a requirement of NFPA, these standards are not enforceable by OSHA. OSHA does not have a separate requirement for DHAs.

Appendix B:  Industries with Heightened Potential for Combustible Dust Hazards

Appendix B is a list of 86 NAICS codes for industries with “heightened potential for combustible dust hazards”, which makes them subject to random selection for inspection under the Combustible Dust NEP. Based on their experience with the NEP since 2008, OSHA removed six industries from the previous list:

  • 022112 Fossil Fuel Electric Power Generation
  • 311821 Cookie and Cracker Manufacturing
  • 325810 Pharmaceutical Preparation Manufacturing
  • 326121 Unlaminated Plastic Profile Shape Manufacturing
  • 335932 Noncurrent Carrying Wiring Device Manufacturing
  • 337920 Blind and Shade Manufacturing

This included two categories from the chemical process industries (NAICS codes 324, 325, and 326). Considering the West Pharmaceutical Services explosion in Kinston, North Carolina on January 29, 2003, it should be no surprise that pharmaceutical preparation manufacturing was included in the original list. Fifteen years later, however, the pharmaceutical industry has not proved to be dangerous as anticipated, at least in terms of combustible dust hazards.

OSHA didn’t just remove industries from Appendix B. It also added six industries:

  • 311812 Commercial Bakeries
  • 316110 Leather and Hide Tanning and Finishing
  • 321214 Truss Manufacturing
  • 321912 Cut Stock, Resawing Lumber, and Planing
  • 325910 Printing Ink Manufacturing
  • 424510 Grain and Field Bean Merchant Wholesalers

Altogether, 19 of the 86 listed industries are part of the chemical process industries.

Appendix C: Sample Citations

Instead of a consolidated regulation on combustible dusts, OSHA relies on 17 different regulations and the General Duty Clause to enforce combustible dust safety in general industry. Seven of those regulations are for specific industries, like the Grain Handling Standard, 29 CFR 1910.272. Others are tangentially related, ranging from forklifts, 29 CFR 1910.178, to warning signs, 29 CFR 1910.145.

The majority of OSHA’s combustible dust enforcement, however, is through the use of three existing regulations and the General Duty Clause.

The first is the Housekeeping Rule, 29 CFR 1910.22. The regulation requires employers to ensure that “all places of employment, passageway, storerooms, service rooms, and walking-working surfaces are kept in a clean, orderly, and sanitary condition.” Even though it sounds like a teenager’s mom telling them to clean their room, it is the basis for most combustible dust citations.

The second is the PPE General Requirements, 29 CFR 1910.132. This regulation requires that “protective equipment, including personal protective equipment for eyes, face, head, and extremities, protective clothing, respiratory devices, and protective shields and barriers, shall be provided, used, and maintained in a sanitary and reliable condition wherever it is necessary by reason of hazards of processes or environment, chemical hazards, radiological hazards, or mechanical irritants encountered in a manner capable of causing injury or impairment in the function of any part of the body through absorption, inhalation or physical contact.” This is the regulation that inspectors are instructed to turn to when they believe that combustible dust hazards warrant the use of flame-retardant and non-static-generating clothing.

The third is the Hazardous (Classified) Locations Standard, 29 CFR 1910.307. In paragraph (c), OSHA requires, consistent with the National Electric Code, that “equipment, wiring methods, and installations of equipment in hazardous (classified) locations shall be intrinsically safe, approved for the hazardous (classified) location, or safe for the hazardous (classified) location.” Locations where combustible dust accumulates or generates clouds are Class II locations.

Finally, there is the General Duty Clause. OSHA turns to this when there it finds otherwise unregulated hazards. To apply, though, the hazard must be “recognized” and there must be a “feasible means of abatement.” So, while OSHA may not enforce industry standards and recommended practices, they will use them as evidence that hazards are recognized, and that complying with those industry standards or recommended practices is at least one feasible means of abatement.

Appendix C gives inspectors instruction and guidance on how to use these regulations and the general duty clause to enforce combustible dust safety.

And the Impact on DHAs?

The new Combustible Dust NEP instructs inspectors to review DHAs to determine whether fire, flash fire, deflagration or explosion hazards exist. But it cautions inspectors that “DHAs should be reviewed toward the end of the inspection when considering a citation or hazard alert letter, and should not be used in determining the scope of the inspection.”

What if you don’t have a DHA? OSHA does not require a DHA in any of its regulations. It is an NFPA requirement, and none of the NFPA standards calling for DHAs have been incorporated by reference into OSHA regulations. So, if an inspector asks to see your DHA and you don’t have one, tell them you don’t have one. There can be no citation for that.

OSHA’s position on DHAs is stated best in the OSHA Technical Manual chapter on combustible dusts. “Remember: OSHA is concerned with the presence of hazards and hazardous conditions, not if the employer has performed a DHA.” (p.49) Hopefully, inspectors got the memo.

Nothing’s Really Changed

The recently revised Combustible Dust National Emphasis Program doesn’t really change much. There is still no comprehensive OSHA Combustible Dust regulation. Some industries were added to program and some were removed from the program. Otherwise, employers with combustible dust hazards should continue to turn to the relevant NFPA standards, the FM Global Datasheets, and the CCPS books for guidance on how to be safer. While it will be really helpful when the NFPA issues its long-awaited standard, NFPA 660, Standard for Combustible Dusts, OSHA does not acknowledge this pending standard.

If this new NEP prompts you to take another look at your combustible dust hazards, good. You’ll be safer because of the extra review. If you haven’t done a DHA, do one. It’s not because you need one to comply with OSHA regulations, but because it will help you to become safer. In general, though, if you have been paying attention to OSHA’s previous guidance on the subject, nothing has changed for you.


  • Mike Schmidt

    With a career in the CPI that began in 1977 with Union Carbide, Mike was profoundly impacted by the 1984 tragedy in Bhopal and has been working on process safety ever since.