OSHA issued a memorandum to Regional Administrators on April 22, 2015 to provide further guidance on evaluating the combustion hazards associated with dust accumulation. Currently, it is possible to infer from OSHA’s Directive, CPL 03-00-008, Combustible Dust National Emphasis Program (Reissued), that any dust accumulation of 1/32nd inch or more presents a deflagration or combustible hazard. However, combustible dust determinations are not that simple. Other factors need to be considered, including the area of dust accumulation (see section 6.1.3.2 of NFPA 654 (2013 edition) and the bulk density of combustible dusts.

The National Fire Protection Association’s consensus standard, NFPA 654, allows dust accumulation to exceed 1/32nd inch for materials with a bulk density less than 75 lb/ft3. According to OSHA’s guidance “[b]ulk densities of combustible dusts depend on many factors including the type of material (e.g. wood, paper, plastic, metal, etc.), the dust particle size, and the dust particle shape.” The memorandum includes the mathematical formula NFPA uses to make this determination. The formula is based on LD (layer depth) and BD (bulk density).  Both layer depth and bulk density are explained more fully but the guidance does instruct Compliance Safety and Health Officers (CSHOs) to consider the bulk density of a dust before determining whether a violation of 1910.22(a)(1), 1910.22(a)(2) or 1910.176(c) has occurred. Tissue dust is used as an example of a very low density dust which may not pose “a deflagration hazard even at an accumulation level of 1/4 inch, covering over five percent of the floor area of 1000 ft2, whichever is less.” The memorandum provides detailed instructions on how to test low density dust accumulations to determine their deflagration risk or combustibility.

According to Bloomberg BNA, OSHA does not anticipate that this guidance will materially alter the outcome of inspections. OSHA believes that most inspections involve dust accumulations so far in excess of the upper allowable limits that only in situations involving light dusts will bulk density be a deciding factor. However, this memorandum makes clear that the accumulation of 1/32nd inch of dust alone does not justify a citation.

A copy of OSHA’s memorandum can be found here.

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Photo of Tressi L. Cordaro Tressi L. Cordaro

Tressi L. Cordaro is a Principal in the Washington, D.C. Region office of Jackson Lewis P.C. She is co-leader of the firm’s Workplace Safety and Health Practice Group. She advises and represents employers on occupational safety and health matters before federal and state…

Tressi L. Cordaro is a Principal in the Washington, D.C. Region office of Jackson Lewis P.C. She is co-leader of the firm’s Workplace Safety and Health Practice Group. She advises and represents employers on occupational safety and health matters before federal and state OSHA enforcement agencies.

Ms. Cordaro has advised employers faced with willful and serious citations as the result of catastrophic events and fatalities, including citations involving multi-million dollar penalties. Ms. Cordaro’s approach to representing an employer cited by OSHA is to seek an efficient resolution of contested citations, reserving litigation as the option if the client’s business objectives cannot otherwise be achieved. As a result, she has secured OSHA withdrawals of citations without the need for litigation.

Ms. Cordaro’s unique experience with government agencies involved in OSHA enforcement enables her to provide employers with especially insightful guidance as to how regulators view OSHA compliance obligations, and evaluate contested cases.

Ms. Cordaro served as the Presidentially-appointed Legal Counsel and Special Advisor to the past Chairman and Commissioner Horace A. Thompson, III at the U.S. Occupational Safety & Health Review Commission (OSHRC) in Washington, DC, the agency that adjudicates contested federal OSHA citations. As the Commissioner’s chief counsel, Ms. Cordaro analyzed all cases presented to the OSHRC and advocated the Commissioner’s position during decisional meetings.

In addition, Ms. Cordaro worked at the U.S. Department of Labor’s Occupational Safety & Health Administration developing OSHA standards, regulations and enforcement and compliance policies, with emphasis on the construction industry. She has in-depth experience on technical issues including, in particular, issues related to cranes and derricks in construction.