In this presentation for AIChE, Timothy Myers provides the background on dust explosions, the elements required to cause them, and the types of materials that can fuel them. He reviews regulations, consensus standards, enforcement issues, and solutions for prevention.

1. Dust Explosions Tim Myers, Ph.D., P.E. Exponent, Inc. 9 Strathmore Road Natick, MA 01760 tmyers@exponent.com (508) 652-8572

2. Recent Catastrophic Dust Explosions

3. Effect of Particle Size on Combustion Rate Source: After Eckhoff, Dust Explosions in the Process Industries (2003).

4. Elements of a Dust Explosion Combustible dust Small particle size Oxidizable Oxidizer (e.g. air) Ignition source Dispersion of dust Confinement

5. Dust Explosions Statistics 1980 – 2005 Other Food Inorganic Coal Plastic Wood Metal 281 Dust explosions and fires 119 Fatalaties 718 Injuries Recent dust explosions have caused damage greater than $100 Million Source: CSB Combustible Dust Hazard Study (2006).

6. OSHA Dust Explosion Hazard Regulations OSHA does not currently have a comprehensive general industry regulation for the prevention of dust explosions. In November 2006 The CSB recommended that OSHA develop regulations based on current NFPA standards. In 2008 and 2009, the U.S. House of Representatives passed the Worker Protection against Combustible Dust Explosions and Fires Act (H.R. 5522) which would have required OSHA to issue rules regulating combustible dusts. April 29, 2009, OSHA announced rulemaking on combustible dust hazards August 2009 – Advanced Notice of Proposed Rulemaking December 2009 – Stakeholder meetings

7. OSHA Combustible Dust National Emphasis Program Effective October 18, 2007 Reissued March 11, 2008 Identified16 industry codes with “more frequent and/or HIGH consequence combustible dust explosions/fires” Identified 48 industry codes that “may have potential for combustible dust explosions/fires” Outreach Targeted inspections NEP and other documents have listed OSHA regulations believed to apply to dust explosions

8. Standards for the Prevention of Dust Fires and Explosions NFPA 61 Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities NFPA 120 Standard for Fire Prevention and Control in Coal Mines NFPA 484 Standard for Combustible Metals 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 the Prevention of Sulfur Fires and Explosions NFPA 664 Standard of Fires and Explosions in Wood Processing and Woodworking Facilities NFPA 850 Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations

9. Summary Recent catastrophic dust explosions have placed an increased emphasis on the prevention and mitigation of dust explosions. In response to CSB recommendations, OSHA introduced a Combustible Dust National Emphasis Program (NEP) and is now proposing combustible dust regulations. NFPA standards and guidelines provide guidance for the prevention and mitigation of dust fires and explosions. NFPA guidelines for preventing and mitigating explosions focuses on: Housekeeping and dust collection Removal of ignition sources Maintenance and training Explosion protection of equipment