DSS238: Safety Share - Asphalt Dust Explosion in Europe

In today’s episode of the Dust Safety Science podcast, we are doing a Safety Share about an asphalt dust explosion in Europe. These quick safety share episodes are designed to swiftly distribute information on incidents, accidents, and significant findings in industries dealing with combustible dust.

A lot of our safety share content comes from sources such as the BC Forest Safety Council, the MAG Group, the Wood Pellet Association of Canada, and others. Today, we’re introducing a safety share from a new group we haven’t featured before – the European Process Safety Center (EPCS). They boast an impressive website, filled with numerous learning sheets that encompass every aspect of process safety hazards, ranging from radiation and explosions to fire, toxicology, and beyond. The site also offers several free webinars, which are highly valuable.

One of the learning sheets highlights an incident involving an explosion of asphaltene or asphalt dust. Though it’s published by the European Process Safety Center, it’s uncertain exactly where in the world this incident occurred; the document doesn’t provide many details about the operation where this event took place.

What is known is that the explosion occurred during the loading of solid ash filling into a trailer akin to a tanker truck. This loading was conducted using a set of bellow cones, housed within a support cone system, to channel the asphaltene into the top of the trailer. An explosion was reported within the support cone, resulting in a primary explosion that dispersed dust in the loading hall, subsequently causing a secondary explosion.

The learning sheet includes some images, though it’s challenging to discern if two of these computer-generated images are actual photographs. They depict what appears to be flame propagation inside the bellow cones, followed by a larger inferno that seems to extend to the rafters or possibly above the truck. The visual representations add a layer of understanding to the incident, although the specific details of the location and operation remain vague.

What Caused the Asphalt Explosion?

After what seems to be an investigation, it was determined that the bonding cable of the last cone was improperly connected. This led to the proposal that the ignition was due to a build-up of static charge in the bellow cone system as the material moved through it.

This static discharge was potent enough to ignite the asphaltene dust inside the cone, triggering the primary explosion and subsequent secondary explosions within the loading hall. However, the learning sheet leaves certain details unclear, such as whether anyone was injured or the extent of the damage sustained by the facility from the deflagration. The mention of both a primary and secondary explosion in the loading hall does indicate that the situation was quite serious, though specifics regarding injuries or damage remain unspecified.

5 Key Recommendations

The safety share document or learning sheet provided five key recommendations for handling such incidents. Here is a brief overview of these recommendations:

Perform a Dust Hazard Analysis: Ensure that dust hazard analysis is conducted using industry best practices and accurate dust characteristics. This involves understanding the specific nature of the dust involved.
Use the Smallest Possible Dust Particle for Testing: Always test explosion properties using the smallest possible dust particle and confirm the actual particle size during operation. This is crucial to avoid false negatives and ensure the sample represents the real hazards. It’s dangerous to rule something out as a possible dust explosion hazard if it turns out to be explosive due to a finer particle concentration.
Housekeeping Measures: Maintaining proper housekeeping is essential to prevent secondary explosions, which can be more severe than primary ones. These secondary explosions can be extremely powerful and destructive, depending on the fuel available in the vicinity. They can lead to significant structural damage, blowing off roofs, destroying support columns, and impacting sprinkler and electrical systems. The outcome can range from a flash fire with thermal radiation hazards to a catastrophic explosion that demolishes the entire building.
Implement Adequate Protection Systems: It’s vital to have sufficient and effective protective measures and safeguards in place against dust explosions. These systems can minimize potential risks and damage.
Ensure Correct Bonding and Grounding: Ensuring the proper and reliable bonding and grounding of metal parts is essential. In the incident described, the asphaltene fell through the yellow metal support cones into the trailer, and the bonding cable of the last cone was not well connected. This resulted in an ignition caused by static discharge.

These recommendations collectively emphasize the importance of meticulous testing, understanding of hazards, thorough housekeeping, proper protection systems, and careful handling of equipment. Adhering to these guidelines can minimize risks and prevent future incidents that might otherwise lead to significant injury and damage.

Conclusion

This Safety Share serves as a valuable lesson and a grim reminder of the dangers present in industries dealing with combustible dust. Though some details of the incident remain vague, the learning sheet’s clear and actionable recommendations stand as a roadmap for others in the industry.

Implementing these best practices ensures that everyone, from operational staff to health and safety managers, remains vigilant and informed about potential hazards. This Safety Share acts not only as a tool for education but as a call to action, urging all stakeholders to take heed of the lessons learned to prevent similar tragedies in the future.

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.