For more than a decade, OSHA has placed an emphasis on combustible dust hazards, which have resulted in numerous deadly incidents over the years. While no OSHA standard directly addresses combustible dust, this has not hindered OSHA enforcement. Instead, OSHA has relied on the General Duty Clause and reference to the National Fire Protection Association (NFPA) standards when citing employers for combustible dust hazards.


What is combustible dust?

OSHA defines combustible dust as “a combustible particulate solid that presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations, regardless of particle size or shape.” When suspended in the right concentration and exposed to an ignition source, these dust particles can lead to fires, deflagrations, or explosions that can cause chain reactions throughout a facility, with potentially deadly results.


National emphasis program

To help protect employees from these hazards, OSHA issued its Combustible Dust National Emphasis Program (NEP) in March of 2008 after a dust explosion at a sugar refinery. The NEP provides inspectors with a set of guidelines to follow when inspecting workplaces in which combustible dusts could be found. The NEP does not create new rules or establish enforcement parameters, but it does provide that OSHA will inspect for, and issue fines related to, combustible dust. While the NEP does not create any specific standard that employers must adhere to, it does state that the NFPA standards should be consulted to identify potential hazards and abatement methods. The NEP also states that the NFPA standards are “useful in providing evidence of industry recognition of the hazard.”

Since adopting the NEP, OSHA inspectors have cited employers for combustible-dust hazards under the General Duty Clause. Due to the fact OSHA has not adopted a specific combustible-dust standard, the General Duty Clause remains OSHA’s primary regulatory enforcement tool to protect employees from these hazards.


General Duty Clause

The General Duty Clause (GDC) requires an employer to provide each employee with “employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm.” The GDC applies to all OSHA-regulated employers, which includes most private sector employers. OSHA routinely relies upon the GDC when a specific OSHA standard is not set forth relative to a particular hazard.

For OSHA to successfully cite a GDC violation, the relevant hazard must be: (1) recognized by the industry or the employer; (2) have caused, or be likely to cause, death or serious physical harm; and (3) have a feasible means available to correct the hazard. OSHA has cited the NFPA combustible-dust standards as evidence of all three GDC requirements. Many OSHA combustible-dust citations also involve poor hazard communication, substandard housekeeping, under-maintained electrical components, a lack of appropriate personal protective equipment, or a lack of fire extinguisher.


NFPA 652

The NFPA previously established standards for specific industries or commodities, and in 2015 created NFPA 652 – Fundamentals of Combustible Dust (NFPA 652). NFPA 652 is intended to be an overarching standard applicable to all facilities and processes. Over the last several years, NFPA 652 has become the go-to standard for all industries with the potential for combustible-dust hazards.

NFPA 652 was also intended to provide facilities with basic guidance on how to handle the hazards associated with combustible dust. However, NFPA 652 guidelines are not always consistent with commodity-specific standards. According to NFPA’s guidelines, when faced with such inconsistencies, the facility can decide which of the two standards is more appropriate for the facility to follow. NFPA 652 provides facility layouts and building requirements for fire protection and requires facilities to understand and monitor the combustion properties of the materials they are using. There are also prescriptive requirements for certain pieces of equipment, and management system requirements for facility operations.


Dust Hazard Analysis

NFPA 652 also requires that all existing and new facilities complete a dust hazard analysis (DHA). The 2015 NFPA 652 standard originally established September 7, 2018 as the deadline to complete a DHA. However, in 2019, NFPA 652 was revised and the deadline was extended to September 7, 2020. That date has not been further extended. Once a DHA has been completed, it must be reviewed and updated every five (5) years. DHAs must also be completed for new processes or equipment added to facilities.

A DHA is intended to review a facility’s processes to identify the presence and potential for combustible dust, site-specific hazards, existing and recommended safeguards, and an implementation plan. The chief objective of a DHA is to identify all the hazards within the facility or process, not just the ones known to be present at the time.

Completion of a DHA does not require hiring an outside consultant, though doing so can often be an efficient approach. A DHA can be completed by an internal team, which can include personnel such as plant managers, maintenance, quality control, shop floor supervisors, or anyone else who is knowledgeable about potential issues associated with combustible dust. For larger facilities and processes, a team of people will likely be required to complete a DHA.

Whether the DHA is led by internal or external personnel, it must be performed by or at the direction of a qualified person. In this case, qualification includes familiarity with combustible dust and the hazards it creates, as well as knowledge of the specific processes being inspected. If a facility does not have internally someone qualified, then it would be necessary to engage an outside consultant capable of performing a DHA.


Enforcement risk

Facilities that have known combustible-dust hazards and have not yet completed a DHA should do so as soon as possible. While NFPA 652 is not a legally binding standard, OSHA looks to the NFPA standards, and NFPA 652 in particular, to establish GDC violations regarding combustible dust.

The absence of a complete and up-to-date DHA presents a citation risk during an OSHA inspection. With the deadline to complete a DHA now passed, facilities with a recognized combustible-dust hazard and an insufficient DHA could be subject to citations for serious or willful violations.

Once a DHA is completed, employers should look to NFPA 652 and the commodity- specific standards to determine what kinds of remedial actions will be necessary to reduce risks to employees and the possibility of an OSHA inspection or citation.

While many employers may be capable of identifying, addressing, and mitigating combustible-dust hazards, including compliance with NFPA 652, it may be necessary or appropriate for others to engage outside technical and legal consultants to ensure their workplace is kept safe.