But, could it have been prevented by managing the barriers to major accident hazards?
It is a well-known fact that major accident hazards are due to the failure of several barriers designed to prevent the major accident: The swiss cheese model of accident causation graphically illustrates that when the holes in the swiss cheese slices align, you get an accident. It only takes one barrier to stop the sequence of events to prevent it.
Source: https://en.wikipedia.org/wiki/Swiss_cheese_model
We may argue that if the large pile of ammonium nitrate that exploded had been sitting there for 3 years or so (reports keep changing), that barriers had been effective until then, or that no hazards had ever materialised.
So, what barriers could have failed so that this accident was made possible? Let us start with the ammonium nitrate cargo that was confiscated…
Barrier 1 – Process for managing dangerous substances
Here we have a couple of barrier elements: The procedure to manage dangerous substances and the training of port staff in this procedure. Did the procedure even exist and available to port staff? Were new staff trained in the management of dangerous substances. In this case, we have two dangerous substances: the fireworks and the ammonium nitrate. Were these cargoes received and stored safely in the port?
Barrier 2 – Fire Prevention
As we know, a fire broke out in a fireworks depot building. There are barriers preventing the start of fires such as electrical PAT testing, fire inspections, leading to improvements such as disposal of excess waste, classification and ordering of inventories, and… proper management of dangerous substances. Were inspections overdue? Were recommendations made and not followed?
Barrier 3– Building Fire Detection and Containment
There are barriers to prevent this fire spreading such as smoke and fire alarms, automatically activated fire suppression systems such as sprinklers or halon/CO2 flooding, and the fire department. We do not know if any of these systems was activated or in progress; but we do know that if activated, they would have been ineffective because the original fire quickly escalated to unmanageable proportions.
Barrier 4 – Warehouse
The warehouse building is a physical barrier itself against the spread of fire. Even though the fire started in a separate building, it quickly affected the warehouse where the fertilizer chemical was contained. Was the warehouse designed with flame and heat resistant wall materials to ensure structural integrity in the case of a fire?
So, what could have happened?
It is likely that one or more of the barriers above failed. Were there sufficient processes to manage dangerous substances? Were personnel trained sufficiently to handle such material? Were sufficient inspection and maintenance activities performed? Did fire detection and firefighting equipment work as intended? Was the warehouse building designed to handle fire and explosion escalation? And specially: Were recommendations followed-up and closed? Barrier management is about identifying the risks, making decisions to fix the impaired barriers and making sure the job is done.
The past years have seen several incidents related to ammonium nitrate. The most recent example that can be compared is the West Fertilizer Company explosion in West, Texas in 2013. The accident caused 15 deaths, over 160 injures and destruction of over 150 buildings. Investigation from this accident showed that improper storage and handling routines were one of the key contributing factors to the accident (Barrier 1).
What can we learn?
In summary, the failure of maybe one or two critical barriers quickly resulted in this overwhelming incident. Perhaps if dangerous substances had been handled properly, they may have been moved to a secure location; if the fire would have been prevented in the first place, or quickly controlled, there would have been no explosion: The sequence of events and the failure of barriers created the major accident.
Barriers not only need to be in place, but managed, controlled and, inspected to ensure that impairments are corrected, and their integrity preserved.
In your industrial facility, are you aware of the impairments in your barriers? Do you know how many of these impairments are dangerously aligned? Have there been near-misses, that always precede a major accident?
Can I apply Barrier Management to my process?
Proper real time barrier management is the state of the art in understanding the real risk of major accident hazards.
Read how the oil and gas industry works with real-time barrier management. The basic principles and technology behind can easily be applied to land-based industries.
Read more about Safetec’s services to properly engineer Barrier Management here.
Check how Eigen’s Safety Barrier Health Monitoring system is helping managers understand how to manage their risk and effectively manage all their barriers in real time.
More information about Eigen’s Safety Barrier Health Monitoring can be found here.
Disclaimer: The thoughts and opinions expressed in this blog post are our own and are not factual.
