DSS030: Five Open Challenges in Combustible Dust Safety

In this episode of the DustSafetyScience Podcast, we talk about five open challenges in combustible dust safety. This is our 30th episode, and it takes a different approach than its predecessors, being a solo show dedicated to the open topics and challenges that continue to affect industries handling combuSouth Sioux City Grain Elevator Explosionstible dust.

Five Open Challenges

Dr. Chris Cloney recently completed a chapter for book dedicated the third volume of the Methods in Chemical Process Safety series. This one dedicated to dust explosions. He wrote about the loss history of dust explosions, followed by lessons learned over the last century and the challenges that remain open. These issues, which have been identified in the U.S. Chemical Safety Board reports and interviews with podcast guests, include:

Housekeeping
Relief venting
Explosion isolation
Ignition control
‘Near miss’ reviews
Employee training programs

Dr. Cloney has also reviewed two safety reports during co-presentations, both of which have identified combustible dust hazards:

Dust theory and nature of, phenomena, cause, and methods of prevention by David Price (1922- published through the NFPA)
Prevention of dust explosions in grain elevators: an achievable goal by the U.S. Department of Agriculture (1980)

All of these reports and interviews have been distilled into five open challenges that we cover in this podcast.

Challenge Number One: A Comprehensive General Industry Standard

In 2004, the U.S. Chemical Safety Board issued a combustible dust hazard report that called for OSHA to create a comprehensive general industry standard on combustible dust. It reiterated the need for a standard after the Imperial Sugar Refinery explosion (2008) the Hoeganaes explosion (2011), the U.S. Ink explosion (2012) and, more recently, the 2018 call to action on combustible dust.

In October 2007, OSHA released the National Emphasis Program on Combustible Dust. It was reissued with some updates after the Imperial Sugar Refinery explosion. In October 2009, OSHA released an advanced notice of proposed rulemaking with regards to combustible dust and in May 2011, they convened an expert forum to discuss the topic.

Today, combustible dust has largely been removed from the U.S. regulatory agenda, although it remains on the Chemical Safety Board’s drivers of critical chemical safety change.

While this comprehensive general industry standard is U.S. specific, it illustrates the struggles that take place across the globe. Dr. Cloney made three recommendations:

The industry standard needs to be specific enough to be actionable. Members of different industries, such as metalworking, wood handling, or 3D printing, need to understand how it applies to their work environment and conditions. Anything too general is difficult to act upon.
Three stakeholders/groups need to be involved. They are: regulators, experts (e.g., members of the Chemical Safety Board or NFPA), and industry representatives. A good example is the 1980s collaboration between OSHA, the U.S. Department of Agriculture and the National Grain and Feed Association. Getting all stakeholders involved ensures that critical bases are covered.
The standard should move towards, not away from a global harmonized solution. Earlier podcast guests have talked about how their countries create new standards by adopting segments of ATEX, VDI, NFPA, and other directives and stitching them together. This fragmented approach makes a global solution impossible.

Challenge Number Two: Response to Dust Fires

There’s one scenario that routinely appears in the Combustible Dust Incident Database. It involves fire in a piece of equipment. Employees try to stop it from spreading and put it out and an explosion occurs, injuring everyone in the vicinity. For example:

Someone opens a smoking dust collector, causing a backdraft explosion.
An employee goes to examine a piece of equipment when an elbow explodes and injures them.
People spray fire extinguishers onto burning dust piles, which consequently flare up.

Recent examples include:

A 2017 fire at a gap mill in Cambria, Wisconsin. When workers gathered around the gap mill, an explosion occured leading to secondary explosions and fatalities.
A 2012 explosion at U.S. Ink in East Rutherford, New Jersey. After an initial explosion, people attacked the fire with extinguishers, but a second explosion occurred and caused injuries.
A January 2019 explosion at a wood processing plant in Kruibeke, Belgium. One worker was killed and three injured when they opened a silo hatch in response to a wood shavings fire.

The biggest losses are suffered by firefighters and first responders. In 2018, six of the 38 injuries from combustible dust explosions happened to firefighters, which indicates that more education in correct response to dust fires is needed.

Challenge Number Three: Difficulties Experienced by Small Operations

A lot of dust explosions occur in small communities and at small facilities.

According to the U.S. Department of Agriculture, there are three million farms in the United States. Many of them have processing equipment for grain storage silos.
There is a vast number of small wood shops with sawdust collection equipment.
At least 24,000 public secondary schools have wood shops and woodworking facilities.

These small operations pose a lot of challenges for the combustible dust community for three primary reasons:

The operator may not fall under OSHA’s jurisdiction. In 2018, OSHA came to investigate a grain elevator explosion in South Sioux City, Nebraska, and determined that the operation didn’t have enough employees to fall under its jurisdiction.
Spreading awareness and understanding is challenging. In Episode #4, Jeramy Slaunwhite talked about how the province of Nova Scotia audited its high schools and found that nearly all of those with a dust collector were not properly protected against dust explosions.
Cost of implementation is an issue. Many small operations may not be able to afford additional safety measures.

Challenge Number Four: Hazards to the Public

There are many reported cases of dust explosions causing serious losses to the public. Recent incidents include:

A 2017 dust explosion on the music video set of the Korean group Oh, My Girl. Colored corn starch settled on the heating elements of the lights and exploded when the lights were turned on.
A cinnamon dust flash fire that occurred in 2017, when the friends of a Danish man dumped cinnamon on him as part of a humorous tradition.
A 2015 flash fire at the Festival of Colors at the New Taipei Water Park in Taiwan. After colored cornstarch was sprayed over a crowd of 1,000 partygoers, blowers from a nearby pool created a dust cloud. Eventually, one of the heating lights ignited the dust cloud, injuring over 500 people.

During a recent presentation for a Powder & Bulk Solids webinar, Dr. Cloney played a video of a January 2017 milk powder protest in Brussels. To protest increased taxes on powdered milk, farmers used leaf blowers and farm equipment to blow huge clouds of milk powder on a building. Although nothing happened in this incident, there were road flares nearby that created a huge potential for injury and death.

Challenge Number Five: Absence of Success Stories

Tim Heneks mentioned in Episode #28 of the podcast that more success stories were needed. We already know what we’re doing wrong, but what are we doing right? We have an open call for listeners to submit their ‘good news’ stories and tell us what they are doing to decrease or eliminate combustible dust hazards in their facilities.

Conclusion

These five open challenges identify weaknesses in combustible dust safety across the globe. By naming them, we stand a better chance of taking control of them and, one day, reducing injuries and fatalities to zero.

If you would like to discuss further, leave your thoughts in the comments section below. If you have questions about the contents of this or any other podcast episode, you can go to our ‘Questions from the Community’ page and submit a text message or video recording. We will then bring someone on to answer these questions in a future episode.