OSHA Revises Combustible Dust Emphasis Program

Effective January 30, OSHA revised its National Emphasis Program (NEP) for combustible dust. The purpose of the NEP update is for OSHA to continue to inspect facilities that generate or handle combustible dusts that are likely to cause fire, flash fire, deflagration, and/or explosion hazards.

The updated combustible dust NEP replaces a directive in place since 2008, and will remain in effect until OSHA cancels it. It does not replace OSHA’s directive for inspection of grain handling facilities, but may affect the scope of coverage.

Industries Added to Target List 

Appendix B of the updated directive includes a revised list of industries that OSHA compliance and enforcement officers will use “for targeting purposes.”

That list now includes:  

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

OSHA added these industries to the targeting list because data collected since the NEP took effect indicates “heightened potential” for combustible dust hazards at their facilities.

The full list of industries targeted for combustible dust starts on page B-1 of the directive.

OSHA also removed six industry groups from the NEP targeting list, including fossil fuel power generation and cookie & cracker manufacturing. OSHA found a lower likelihood of combustible dust hazards at these types of workplaces.

What is Combustible Dust?

OSHA’s NEP includes a definition for combustible dust based on relevant NFPA standards, which reads:

Combustible dust. A finely divided combustible particulate solid that presents a flash-fire hazard or explosion hazard when suspended in air or the process-specific oxidizing medium over a range of concentrations.

Dusts known to cause these hazards include:

• Metal dust such as aluminum and magnesium.
• Wood dust.
• Coal and other carbon dusts.
• Plastic dust and additives.
• Biosolids.
• Other organic dust such as sugar, flour, paper, soap, and dried blood.
• Certain textile materials.

The directive states that "the majority of combustible dust hazards resulting in fires and explosions involved combustible dust generated during the manufacturing and processing of agricultural, food, wood, and metal products. In 2018, wood and food products made up 70% of materials involved in combustible dust fires and explosions. 

OSHA Website | Combustible Dust: An Explosion Hazard

Combustible dusts are dusts that, when suspended in the air in a confined space and exposed to an ignition source, can ignite or explode—often with catastrophic results. These dusts may accumulate on rafters or equipment until they are shaken lose and become airborne due to an explosion or other “primary event.”

This video from the Chemical Safety and Hazard Investigation Board (CSB) shows what happened during a combustible dust explosion at a sugar plant in 2008 that killed 14 people and injured 38 others. 
 

What OSHA Regulations Apply to Combustible Dust?

Since initiating the Combustible Dust NEP in 2007, OSHA has conducted approximately 600 inspections per year under the program. While there is no specific OSHA Standard for combustible dust, the Agency relies on multiple workplace health & safety requirements, as well as the General Duty Clause of the OSH Act, to cite violations. 

If dust is found accumulated on surfaces or in material storage areas, for example, OSHA may cite the employer for housekeeping violations under the general industry Standards for Walking-Working Surfaces (1910.22(a)(1)—(2)) or Materials Handling and Storage (1910.176(c)).  

OSHA may also cite an employer for noncompliance with workplace ventilation standards in 1910.94, personal protective equipment (PPE) requirements in 1910.132, or hazard communication information and training requirements in 1910.1200 for hazardous chemicals, among others. .  

Combustible Dust and the OSH Act General Duty Clause

The General Duty Clause of the OSH Act (Section 5(a)(1)) requires employers to provide a workplace for employees that is free of recognized hazards that can cause serious injury or illness. In its combustible dust directive for enforcement personnel, OSHA lists scenarios that could result in a citation for a violation of the General Duty Clause related to combustible dust.

The following are examples of workplace conditions for which a general duty clause citation (See Appendix C for sample citations) may be issued:

• Problems related to dust collectors, e.g., dust collection equipment located inside the building (however, there are some exceptions) and dust collectors returning air back inside the building.

• Ductwork-related problems, e.g., the ductwork not being grounded and ductwork not constructed of metal.

• Improperly designed deflagration venting (venting to areas where employees are likely to be exposed to explosion/deflagration hazards).

• Processing and material handling equipment, such as, mixers, blenders, pulverizers, mills, dryers, ovens, filters, dust collectors, pneumatic conveyors, and screw conveyors, are not protected by deflagration suppression systems.

• Blowers, collection systems, and exhaust systems used at sawmills that are not designed, constructed, or maintained properly.

Tags: combustible dust, enforcement, OSHA compliance, safety inspections