The U.S. Department of Labor’s Occupational Safety & Health Administration (OSHA) continues to issue citations for alleged violations of various general industry standards (such as general housekeeping and electrical standards) and Section 5(a)(1) of the Occupational Safety and Health Act, the General Duty Clause (“GDC”), for alleged workplace exposure to fire and/or explosion hazards from “combustible dust,” despite the lack of a clear and comprehensive general industry standard governing employers’ handling of combustible dusts. 

Definition of “Combustible Dust”

Although there is no single, universally accepted definition of “combustible dust,” nor a standard method for sampling dust to determine its combustibility, OSHA has defined “combustible dust” in at least one rulemaking document to include “all combustible particulate solids of any size, shape, or chemical composition that could present a fire or deflagration hazard when suspended in air or other oxidizing medium.” The hazards of combustible dust encompass a wide range of materials, industries, and processes. Materials that may form combustible dust include, but are not limited to, wood, coal, plastics, biosolids, candy, sugar, spice, starch, flour, feed, grain, fertilizer, tobacco, paper, soap, rubber, drugs, dried blood, dyes, certain textiles, and metals. In order for a dust fire to occur, three elements are required (combustible dust; ignition source; and oxygen), whereas a dust explosion requires two additional elements (dispersion of dust particles in sufficient quantity and concentration; and confinement of the dust cloud). 

2014 Enforcement Case: Powderpart Inc.

Last spring, a Woburn, Massachusetts-based 3-D printing company, Powderpart Inc., was cited by OSHA for multiple alleged violations involving combustible dust hazards, including violations of the GDC for failure to furnish 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 to his employees.” The inspection followed a November 5, 2013 explosion and fire that inflicted third-degree burns on a company employee. Powderpart allegedly failed to eliminate known sources of potential ignition and follow pertinent instructions from equipment manufacturers, did not alert Woburn Fire Department to the workplace presence of hazardous materials, and located an employee workstation and flammable powders next to an area with explosion potential, among other alleged violations, according to OSHA. OSHA’s then acting regional administrator for New England stated, “Establishments that use metal powders in this new technology need to scrutinize their processes and take steps to prevent and protect their employees from fire and explosion hazards that arise with these materials.” More information on the alleged violations, is available at the OSHA website. This enforcement action is one of several this year involving combustible dusts.

Background and History of OSHA’s Regulation of Combustible Dust

OSHA’s amplified enforcement of workplaces generating and/or handling combustible dusts began in 2006, when, following three significant combustible dust-related industrial explosions in North Carolina, Kentucky, and Indiana, the U.S. Chemical Safety and Hazard Investigation Board (CSB) published an Investigation Report recommending, in part, that OSHA implement a special emphasis inspection program targeting industries particularly at risk for dust explosions and issue “a comprehensive combustible dust standard for general industry that addresses hazard assessment, engineering controls, housekeeping, and worker training.” CSB recommended that the new standard be based on National Fire Protection Association (NFPA) standards (in particular, NFPA 654 and NFPA 484).

Since issuance of CSB’s Investigation Report, OSHA has initiated a National Emphasis Program (“NEP”) to increase OSHA’s enforcement of industries generating and handling combustible dust. As part of the NEP, OSHA issued a Compliance Directive that provides guidance to OSHA inspectors on how to inspect workplaces for combustible dust hazards. In October 2009, OSHA issued a Status Report on this NEP, stating OSHA had conducted more than 1,000 inspections involving 64 industries, and that only 18 to 22% of the facilities inspected were found to be in compliance with OSHA requirements.

Also in October 2009, OSHA published an Advance Notice of Proposed Rulemaking (ANPR) announcing its intent to develop a comprehensive combustible dust standard for general industry, and requesting comments on various issues related to the hazards of combustible dust in the workplace. OSHA recognized that it currently has no single, comprehensive standard addressing combustible dust hazards across all industries and that its existing general industry standards address some, but not all, of the potential hazards. Since publishing the ANPR, OSHA has held multiple stakeholder meetings on this rulemaking. The next step in the rulemaking process is for a Small Business Regulatory Enforcement Fairness Act Panel to review the rule’s impact on small businesses. However, the Panel has been repeatedly postponed since 2011. DOL’s most recent Semiannual Regulatory Agenda estimates that the Panel will be held in December 2014.

CSB considers the delay in promulgating this “urgently needed” standard to be an “unacceptable response,” and, in July 2013, designated this standard as a “most wanted safety improvement,” thus indicating CSB will be strongly encouraging OSHA to propose a comprehensive standard as soon as possible.

Recommended Steps for Industry

Although there is no single standard for determining how to assess and mitigate potential hazards of combustible dusts in the workplace, existing OSHA general industry standards and NFPA standards are instructive for companies that believe they may generate and/or handle combustible dusts. If a company’s testing confirms the presence of combustible dust in the workplace, that company should evaluate its compliance with OSHA standards and NFPA standards addressing combustible dusts, and consider developing a written program outlining measures for mitigating the potential hazards.

Some of the OSHA general industry standards that address combustible dusts include, but are not limited to:

• Hazard Communication Standard, 29 CFR 1910.1200

• Electrical Standard, Hazardous (Classified) Location, 29 CFR 1910.307

• Permit-Required Confined Spaces Standard, 29 CFR 1910.146

• Housekeeping Standard, 29 CFR 1910.22(a)

• Housekeeping in Storage Areas Standard, 29 CFR 1910.176(c)

• Ventilation Standard, 29 CFR 1910.94

• Powered Industrial Trucks Standard, 29 CFR 1910.178

• Occasional Use of Flammable or Ignitable Materials Standard, 29 CFR 1910.334(d)

• Welding, Cutting and Brazing Standard, 29 CFR 1910.252

• Personal Protective Equipment Standard, 29 CFR 1910.132

Some of the NFPA standards that address combustible dusts include, but are not limited to:

• NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities

• NFPA 68, Guide for Venting of Deflagrations

• NFPA 69, Standard on Explosion Prevention Systems

• NFPA 70, National Electrical Code

• NFPA 77, Recommended Practice on Static Electricity

• NFPA 85, Boiler and Combustion Systems Hazards Code

• NFPA 86, Standard for Ovens and Furnaces

• NFPA 91, Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids

• NFPA 484, Standard for Combustible Metals, Metal Powders, and Metal Dusts

• NFPA 499, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas

• NFPA 654, Standard for the Prevention of Fires 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

OSHA has regularly stated that NFPA standards that have not been specifically incorporated into OSHA standards or adopted by state or local jurisdictions should be considered by companies as guidance. At the same time, however, the NEP Compliance Directive instructs OSHA inspectors to consult the NFPA standards to “obtain evidence of hazard recognition and feasible abatement methods” to support a citation under the GDC. Consequently, companies should consult NFPAs when evaluating and mitigating potential combustible dust hazards at their facilities.