Every day, millions of containers are shipped around the world, some of them carrying Dangerous Goods (DG). To enhance the safe transport of dangerous goods by sea, and protect the marine environment, the International Maritime Dangerous Goods (IMDG) Code was developed for containerized cargo. This contains advice on terminology, packaging, labelling, stowage, handling and emergency response. As well as the IMDG code, the International Maritime Solid Bulk Code (IMSBC) was developed to deal with the dangers and issues arising with the shipment of bulk cargoes, where often the dangers only become apparent when there are significant quantities of material.
Container goods and IMDG cargoes
One of the major issues faced in container shipping today, and indeed for the last 40 years, is mis-declared cargo. Due to the complexity of the IMDG code, mistakes are often made due to mis-understanding the code and the testing requirements. We often see this when inspecting relatively undamaged containers in the area surrounding the location of a fire – for example small quantities of dangerous cargo loaded in with general goods, or where formulations have been changed and subsequent testing is not undertaken. However, there is a more insidious side, with shippers purposely mis-declaring dangerous goods to avoid the extra costs associated with shipping the cargo.
Whilst there are many goods and chemicals that have caused fires on ships, we have repeatedly seen the same cargoes being mis-declared and shipped as non-dangerous goods, namely:
- Calcium hypochlorite (20 plus large-scale incidents)
- Lithium ion batteries (at least 2 – 3 large-scale incidents a year for the last 5 years)
- Charcoal and charcoal tablets (around 2 – 4 large-scale incidents a year)
- Metal swarf (1 or 2 incidents a year)
- Organic peroxides (regularly seen, with 1 or 2 incidents a year)
Calcium hypochlorite (CH) is a chemical compound that appears as a white-yellow solid. It is soluble in water with a distinct chlorine smell. It is a strong oxidizing agent, and is widely used in swimming pools and for water purification. CH is classified as an IMDG class 5.2 cargo and has six separate entries in the IMDG code, depending on the water content and the available chlorine content. Whilst it is a poor excuse, with six separate entries, it is not surprising that there are mis-declarations.
CH gained notoriety in the late 1960s and early 1970s, when it was involved in several major explosions and fires on ships. It was apparently not involved in any similar shipboard incidents until the late 1990s. It was known, of course, that the substance was an oxidizing agent capable in certain circumstances of reacting with organic materials to cause a fire. However, it is also self-reactive, which means that it can undergo thermal decomposition on its own. This is why the material loses chlorine over time when stored at normal ambient temperatures, as it slowly decomposes. The chemical reaction which causes this loss generates heat and thus the rate of the reaction can increase if this heat is not dissipated. As a general rule, chemical reactions are faster at higher temperatures. At elevated temperatures, this self-reactive behaviour can reach ‘criticality’, at which point the rate of decomposition accelerates rapidly, leading to the potential for an explosion.
Over the last 10 years, there has been at least one incident a year, and sometimes more, related to CH. These have included major explosions and fires, some causing loss of life and severe damage such as that seen in the photographs below.
In other incidents, you can clearly see the power and effects of the explosion on board, with disrupted and damaged containers:
Lithium ion batteries
Lithuim ion (Li-ion) batteries, because of their high energy density, are used in a huge variety of products, from mobile telephones to large uninterruptable power supplies. This high energy density also means they have the potential to short circuit or go into thermal runaway, something that has happened on many occasions when carried in containers on board vessels. We have experienced fires with Li-ion batteries in equipment, shipped as separately packaged batteries, as recycled batteries and, on many occasions, as mis-declared cargo.
The typical case we encounter is a fire involving mobile telephone batteries that have been mis-declared as ‘phone accessories’. Instead, upon inspection, we see thousands of batteries stored together, with very little separation between them; if heating starts in one, there is very little to prevent it spreading to the others. One of the major risks we have found, both on ships and in land investigations, is the fact that flammable gases are given off by the batteries when they are involved in a fire. Furthermore, we have also seen occasions where the batteries on fire have become water reactive, making fire-fighting extremely difficult.
This has become a significant problem cargo in the last 10 years, with a variety of different charcoal products being shipped from Asia. Charcoal is made from wood products, which are heated in a reducing atmosphere (without oxygen), thereby lowering the water content and carbonising the wood. The product burns much more easily than wood and has been used as a fuel source for thousands of years. However, if the manufacturing process is poor, or if the product is not allowed to cool or weather prior to loading, then it will self-heat to ignition. If the container is below deck, this leads to an extremely serious fire that is very hard to extinguish, often continuing to burn despite having been submerged underwater.
The photographs below show a fire involving charcoal tablets, which are used for hookah water pipes. Things became very interesting for the shore team when the still-burning container was landed on the quayside and the shock dispersed fine powdered charcoal, causing a fire ball to extend approximately 20 metres up and over the gantry crane. The shore fire brigade gave up trying to extinguish the container after 20 hours of pumping water and foam inside, eventually agreeing to let it burn itself out (which took around 10 days).
IMSBC cargoes cover bulk cargo shipments, such as coal, woodpellets, seedcakes and ores. Many of these cargoes are considered safe when carried in small quantities, but when carried in bulk they can have very different properties. For example, with coal cargoes, very few problems are encountered when you have small quantities of 10 – 50 mt, but put it into a large pile or into a ship’s hold, and with 8 – 12,000 mt all sorts of issues can occur. For coal, the two principle risks are the generation of methane and self-heating, which can make for interesting times when you have a hold with a fire and high levels of a highly flammable gas inside!
The types of issues that we generally encounter with bulk cargoes are:
- Self-heating, leading to fires or cargo spoilage;
- The generation of flammable or toxic gases; and
- Poor training or lack of understanding on behalf of the ship’s crew
When a fire occurs on a bulk carrier, it can quickly become extremely difficult to deal with, and knowledge of prior incidents and methods that work are a vital component in successfully dealing with such an incident. Also, by taking the correct course of action for the cargo, the majority of it can often be saved and still used (for example using freshwater not seawater on an agricultural cargo).
Health and safety
There can often be an interesting health and safety side to the incidents on board ships, such as a fire department spraying a container down with an active fire inside wearing full BA, and then sending the stevedores, wearing shorts and trainers, to open the container doors…
In summary, fire investigation and forensic science work throughout Asia offers both interesting and varied work and is something that can be deeply rewarding. Experience is paramount when dealing with live ship fires. You may want to see if there is a fire expert that has relevant experience in the type of incident at hand if you attend one of these scenes, and make use of that expertise.
Whilst the work that we undertake is generally post-fire investigation, Hawkins frequently provides assistance to ships’ crews, Fire Departments and salvors on fire-fighting, gas detection and health & safety issues when dealing with a live fire on board a ship.
For more information, go to www.hawkins.biz