We’ve devoted many podcast episodes to case studies, due to insights they can provide and the lessons we can take away. Today, we’ll be talking about a facility that had multiple incidents over time and what the true cost of ignoring your combustible dust challenges can be.
We had been watching this facility for a while. It had experienced multiple fires and explosions in the past and we often track these facilities over time to see how they’re making out. Unfortunately, we recently learned that they were shutting down. However, reviewing the company’s history can illustrate the true cost of ignoring your combustible dust challenges.
What Happened?
We’re not going to name the company in this episode. Instead, we’ll be going over the general information about this case. We have a handful of fire investigation reports and have some OSHA citations that helped us put a timeline together.
The facility was built in late 2016. They had three to four dozen employees and were located in a town of about 2,000 people. In the three-year period that it was operating, they had at least six fires. One of them resulted from a dust explosion that injured a worker with first and second degree burns and sent them to the hospital.
They had five OSHA inspections, three with citation penalties. There was a lot of equipment damage from these fires. They had challenges with building permits. They had challenges with lawsuits. Challenges with fines from their municipality. All of these difficulties were due fire and explosion safety issues, particularly combustible dust.
A few months after opening in December 2016, they had a fire that destroyed their wet scrubber. There is not a lot of information on this fire but it played a big role in the negative public image that began to grow due to the very bad smell coming from the plant. This eventually led to a lawsuit filed against the company by the commuinity.
A few months later, in June 2017, they had a baghouse fire, which resulted in $200,000 in damages. A month later, in July, they had a dust explosion that injured a worker and resulted in OSHA fines. In October that same year, they had a consultant come in to do a walkthrough and review of their combustible dust program.
This party tested their dust, found it explosible, and recommended isolation and explosion protection on the dust collector. They couldn’t see venting on the dust collector but were told that explosion doors were on the top of the unit. Regarding housekeeping, there was a program for the cleaning of the floor but dust had built up on the walls and elevated surfaces. The report stated that the facility had an elevated risk of flash fire and dust explosion hazards.
Unfortunately, in February 2018, they had another scrubber fire that destroyed the scrubber again. In March, there were OSHA citation penalties related to combustible dust. In May and November and December of 2018, they had fires again in their dust collection system. In December 2019, an article came out saying that they were shutting down.
A Closer Look at the Incidents
We obtained some information about these incidents from fire investigation reports that are publicly available.
The fire in the baghouse occurred in June 2017, a few months after their wet scrubber was destroyed in a fire. What happened is that they shut down the process to repair a mixer and those repairs took longer than anticipated.
Having that auger shut down for so long allowed more wet material into the process. This wet material sticks to the sides of the drum dryer and starts to burn off. In this case, and in many of the other fires that they experienced, those burning embers were sucked into the conveyance system and eventually ended up in the dust collector, where they caused a fire.
It does mention in the fire marshal’s report that there was a spark detection system. It did detect the sparks going into the dust collector but failed to activate a suppression system because the electrical breaker tripped. The report estimates the loss at $200,000 for the baghouse. It also notes that there already had been multiple fires at this facility and most appeared to have a similar origin and cause. Again, it doesn’t specifically say what these fires are, but it does hint at these scrubber fires and earlier issues that were of similar origin and nature.
A month later, in July of 2017, they had a dust explosion that injured an employee. We couldn’t find much information on this event other than that it had happened, but looking at the consultant report, it appears that the explosion occurred in the ducting between the dust collector and the fan. The report adds that the company went on to add explosion vents to that section of ducting.
The fire marshal report notes that there were five fires already at this facility. We’ve accounted for at least three. There are two others that happened sometime between this incident and when the facility closed.
In one case, the maintenance staff reported burning dust underneath the fan unit that was located on ground level. Earlier in the day, they had removed some of the material with shovels and it appeared discoloured. Eventually, they noticed the fire in this area and in the fan system. They put it out by pouring water into the dust collection unit. It doesn’t state how much the loss was for this equipment fire.
In November of 2018, a similar fire occurred. What is startling is how it looks like a big section of the fire marshal’s report was copy and pasted from the May incident. The part about the fan, the processing operation and how the fire started is in the exact same words. That’s how routinely they were seeing fires at these facilities and now the fire marshall was copying and pasting from one report to the other because it’s like the same thing happened again.
This report also addressed the difficulties the fire department was having. The building itself was still on temporary permit as a building under construction so the fire department didn’t have the ability to enforce a fire code. The facility was still governed by the building code officials.
Later in December 2018, there was a fire in the dust collector again. According to the report, this fire started when the workers were moving filters from the baghouse. One employee had used a grinder to cut the bolt holding the filters in place and that ended up igniting a fire in the baghouse hopper down below.
Conclusion
This final incident shows the level of awareness and the level of safety at this facility. They had had all these fires and an injured employee, but they were still doing things like having hot work going on inside the dust collector while combustible material was around. The proper level understanding of the hazards and the risk associated with these materials still wasn’t there. The sad thing is that there are likely other facilities that operate under similar conditions, and until dust safety is better understood, more businesses like this one will likely be closing down.
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.
Resources mentioned
Dust Safety Science
Combustible Dust Incident Database
Dust Safety Science Podcast
Questions from the Community
Dust Safety Academy
2021 Global Dust Safety Conference
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DSS109: Case Study – The True Cost of Ignoring Your Combustible Dust Challenges
