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Comment PDF Environment, Health, Safety & Security

Combustible Dust Fires and Explosions: Recent Data and Lessons Learned

By Chris Cloney, DustEx Research Ltd. |

A review of recent data from the Combustible Dust Incident Database provides insights into dust-related process safety

Fires and explosions in facilities that handle combustible dust remain an ongoing focus of process safety efforts across many areas of the chemical process industries (CPI). But how many dust-related safety incidents occur each year? This question is a major driver behind the formation of the Combustible Dust Incident Database (CDID; Halifax, N.S., Canada; www.dustsafetyscience.com). Created in 2016, the CDID features a twice-yearly report on fires and explosions having to do with combustible dusts. The CDID is an online portal with the purpose of reporting, tracking and generating lessons learned from fire and explosion incidents around the world. The database is meant as a tool for technical decision makers to anticipate upcoming difficulties and process safety trends in their industries, and to give the powder-handing community a platform to measure and manage combustible dust hazards.

The information collected and tabulated on combustible-dust incidents in the CDID is now helping to determine trends and tendencies in the materials, industries and equipment involved with these hazards.

This article outlines the findings from the incident reporting completed to date. Comparisons are made between the CDID information and historical combustible-dust explosion data within the U.S. Also, an overview of the personal and financial loss resulting from these types of incidents is provided.

The incident research discussed here is based on publicly available information, including news stories and other resources accessible by Internet search engines, as well as social media sharing, government sources and industry repositories. It is important to note that articles may contain incomplete or, in some cases, incorrect information. Furthermore, dust fires and explosions often go unreported, and the totals reflected here may vastly underestimate the total magnitude of the problem. This is especially true internationally, where the news coverage is sometimes limited.

 

Incident reporting

The first incident report [1] was released in 2016 and covered combustible dust explosions within North America. In 2016, 31 explosions were reported in the U.S. and two were reported in Canada. These incidents caused a reported total of 22 injuries and three fatalities in 2016.

In 2017 mid-year and year-end incident reports were released [2]. The year-end report covered both combustible dust fires and explosions around the world. In North America, 132 fires, 32 explosions, 61 injuries, and six fatalities were recorded. Four of the explosions were reported in Canada, while the other 28 were in the U.S. Internationally, 37 fires, 36 explosions, 102 injuries and seven fatalities were recorded.

The 2018 mid-year incident report [3] was released in August 2018. In addition to global fire and explosion incidents, the Occupational Safety and Health Administration (OSHA; Washington, D.C.; www.osha.gov) citations, upcoming events, and new technology and products were also featured. In the first six months of 2018, 75 fires, 14 explosions, nine injuries and one fatality were reported in North America. One of these explosions occurred in Canada and 13 within the U.S. Internationally, 14 fires, 12 explosions, 31 injuries, and eight fatalities were recorded.

The reports can be downloaded by navigating to the following link: https://dustsafetyscience.com/chemical-engineering-magazine-2018.

Comparison to historical data

The most comprehensive analysis of combustible dust incidents in the U.S. is the Combustible Dust Hazard Study [4], published by the U.S. Chemical Safety Board (CSB; www.csb.gov). In this report, the CSB reviewed combustible-dust flash fires and explosions over a 26-year period between 1980 and 2005. Comparing the average number of explosions, injuries and fatalities to those from the CDID illustrates how the loss from these incidents may be evolving over time (Table 1).

t1

The CSB report shows an increasing trend in the number of combustible-dust incidents, injuries and fatalities, with the numbers almost doubling during the 20-year period from 1980 to 2001. The CSB cautions in their report that this increase may be due to limitations in previous reporting, including that the earlier incidents were under-reported.

The more recent CDID data show a steady continuation in the number of recorded dust-related explosions per year. The total increased by another 50% in the 10 years since the CSB report was published. However, the incident reports also suggest that the overall number of injuries and fatalities may be flattening or decreasing compared to the number of incidents. This tentatively suggests that an emphasis on combustible dust awareness, prevention and protection practices over the last decade may be reducing the average severity of any given explosion. It is again important to note that under-reporting in previous data may influence this conclusion. Furthermore, although the severity may be decreasing, neither dataset shows any single year with zero fatalities due to dust explosions in the U.S. since 1983.

 

Materials and industries

From the 2018 CDID incident reporting, wood processing, food processing and agricultural activities account for almost 60% of the dust-related fire and explosion incidents. Automotive manufacturing, metal working, power generation and mining contributed an additional 17%. The remaining 24% of incidents occurred in other industries, including pulp and paper, education, coatings, oil and gas, textiles and recycling.

Very frequently, materials involved in wood-product incidents were specified as sawdust or wood dust, and materials involved in food processing or agriculture were specified as grain dust. In cases were specific materials were named, pine chips, cellulose, corn, pecan, cocoa, flour, cereal, barley and spices were implicated in dust incidents. Although not broken out in the data, coal dust accounted for almost 7% of the total incidents. In cases involving metal dusts, aluminum, titanium, magnesium and iron were cited most often.

 

Equipment and causes

Dust collectors tend to have the highest number of total incidents of all equipment involved in powder processing. However, the 2018 incident data suggest that these were more often fires than explosions. It is often difficult to distinguish between storage silos and elevators — these two terms are often used synonymously in much of the news reporting. Overall, storage silos, elevators and conveyors made up half of the explosion incidents, while accounting for a smaller proportion of the overall fires (Table 2). Other equipment includes mills, shakers, grinders, saws, dryers and cyclones.

t2

Often, very little information is available that points to the initiating cause of combustible dust fire and explosion incidents. In specific cases highlighted in the reports, hot work, including welding and cutting metal, are listed as the initiating cause. Sometimes machine sparking and static electricity are indicated in news reports, although it is rare to have this substantiated by a formal technical review. Further development of the CDID will focus on working with local fire departments and government organizations to better communicate these causes when an official investigation has been performed.

 

Loss overview

It is instructive to organize the combustible-dust incident data in terms of different types of loss. This comparison provides some information about how fires and explosions impact injury totals, fatalities and facility damages individually, and allows trends from different materials involved in processing operations to be explored.

Global data from the first half of 2018 indicated that 89% of the fatalities from dust incidents occurred due to explosions. With regard to injuries, 70% occurred from explosions, while 30% were the result of fires. The total breakdown of injuries and fatalities from fires and explosions is as follows: Explosions caused 28 injuries and eight fatalities, while fires caused 12 Injuries and one fatality.

This suggests that explosions tend to be more severe in terms of injuries and lives lost than facility fires. However, the trend for facility damages shows the reverse. Out of the eleven incidents with reported losses of $1 million and above, eight were from fires and three were from explosions. This highlights the importance of both fire and explosion prevention in facility safety measures.

In terms of materials involved, the number of fires, explosions, injuries and fatalities for the two most common categories are as follows: Wood products were involved in 33 fires, five explosions, 10 injuries and 0 fatalities, while food products were involved in 24 fires, 12 explosions, 14 injuries and eight fatalities.

Although both categories are responsible for a similar total number of incidents, fires appear to be more prevalent in wood processing facilities and explosions tend to be more common in food processing and agriculture. In cross-referencing these data with the equipment data provided earlier, these differences may be due to more frequent use of dust-collection systems in wood-dust-handling facilities and more frequent use of silos and conveyors for food production.

As a result of the higher number of explosions, food products have a larger number of high-severity incidents in terms of injuries and fatalities. In terms of facility damage, industry activities involving wood products resulted in more incidents that generated $1 million or more in losses. A summary of the high-damage incidents is shown in Table 3. Six of these incidents involved wood dust, sawdust, wood pellets and wood shavings. Five of these were fires and one was an explosion. This again demonstrates that both fire and explosion hazards need to be addressed in industries handling combustible dust.

t3

Additional information on specific incidents can be found at www.dustsafetyscience.com. Ref. 5 contains an example of incident summaries.

Concluding remarks

After comparing data from the CDID, including findings from the 2018 mid-year incident report, with historical data from the CSB, the case can be made that combustible dust is a safety issue that deserves continued attention and focus. The data also suggest that efforts related to dust safety on the part of CPI companies, government agencies and other industry organizations may be having a positive effect: while the number of reported dust-explosion incidents is increasing over the past 40-year period, the number of injuries and fatalities per year since 2001 to 2005 may be leveling out, or even decreasing.

Other tentative conclusions that can be drawn from the data involve the materials and equipment types most likely to present a dust-safety hazard. The most frequently cited materials involved in combustible dust incidents include wood products and food products. While dust collectors had the overall largest number of incidents in the first half of 2018, they largely involved fires. Explosions occurred more frequently in storage silos, elevators and conveying equipment. The data available point to some gaps in information: often the initiating cause of fires and explosions involving combustible dusts is unavailable. This provides motivation for future efforts into improved procedures for collecting this information.

Information on the losses involving injuries, fatalities, and facility damages from dust-related incidents reinforces the need for countermeasures for both explosions and fires.

The CDID is actively collecting more information recording incidents as they occur. The ongoing analysis and richer trove of data will allow for more detailed explorations of fire and explosion incidents in industries outside of wood and food processing.

Edited by Scott Jenkins

 

Acknowledgements

The author would like to acknowledge that support for the CDID and incident reporting comes from member companies and report sponsors. A list of the 2018 report sponsors is provided here:

  • ANPAK
  • AT Industrial Products
  • Boss Products LLC
  • CV Technology
  • Delfin Industrial Corp.
  • Fauske & Associates LLC
  • IEP Technologies
  • Nilfisk
  • Rembe
  • Fike Corp.
  • Camfil
  • ExNB
  • EPM Consulting
  • Sintrol
  • SpaceVac
  • BWF Envirotech
  • Power & Bulk Solids
  • Bulk Inside
  • Jensen Hughes

Author

Chris-Cloney-Dust-Explosion-ResearcherChris Cloney (PEng.) is the director and lead researcher at DustEx Research Ltd., (60 Bridgeview Drive, Halifax, N.S., Canada B3P 2M4; Phone: 902-452-3205; Email: chris@dustsafetyscience.com), a company with a worldwide focus on increasing awareness of combustible dust hazards and reducing personal and financial loss from fire and explosion incidents. Cloney spent five years working as an engineering consultant and software developer in the defense industries focusing on detonation, explosion, and blast research. Upon completing his Ph.D. thesis in the area of modeling coal dust and hybrid mixture deflagration, he moved into the world of online education focusing on sharing and connecting the combustible dust community.

References

1. Cloney, Chris. “2016 Combustible Dust Incident Report (North America) – Version #2” DustEx Research Ltd. 2016. Retrieve from www.dustsafetyscience.com/2016-Report

2. Cloney, Chris. “2017 Combustible Dust Incident Report – Version #1” DustEx Research Ltd. 2017. Retrieved from www.dustsafetyscience.com/2017-Report

3. Cloney, Chris. “2018 Mid-Year Combustible Dust Incident Report – Version #1” DustEx Research Ltd. 2018. Retrieve from www.dustsafetyscience.com/2018-Report

4. U.S. Chemical Safety and Hazard Investigation Board (CSB). “Investigation Report – Combustible Dust Hazard Study”. Report No 2006-H-1. 2006.

5. CDID incident summary for San Juan, NM, found https://dustsafetyscience.com/coal-fire-san-juan-new-mexico/.

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