Safe carriage of dangerous goods in containers.
The International Group of P&I Clubs and the shipping line members of the Cargo Incident Notification System (CINS) have recently produced a new set of guidelines for the carriage of calcium hypochlorite in containers. UK Club risk assessor, David Nichol, discusses why it was considered necessary to update guidance for a cargo with a history of being implicated in ship fires as well as the wider problem of the mis-declaration of dangerous goods.
If a fire breaks out at sea, the crew do not have the option of simply evacuating the building and waiting for the fire brigade to turn up. The crew have to deal with it themselves. Locating the exact source of a fire on board a fully laden container ship and fighting it with the limited manpower and resources available is a daunting task for the crew. It is imperative for the safety of the ship and crew that all necessary steps are taken to handle and stow dangerous goods in such a way that reduces the risk of an emergency incident and that in the event of fire, the crew have the information they need to respond quickly with the appropriate fire fighting measures. To enable this, a ship’s master must be provided with a correct, universally recognised description of the goods and the potential hazards they may present.
During David’s time as a ship surveyor, he was involved in the investigation of a violent explosion and fire on board a container ship transiting the Mediterranean Sea. The incident led to the deaths of a number of crew members and caused extensive structural damage to the ship. It was determined that the explosion was the result of inflammable gas within one of the holds which was ignited by the crew performing maintenance on deck. The gas had leaked from a number of containers stuffed with Expandable Polystyrene Beads, which may not seem particularly hazardous to the layman but is a material containing heavier than air pentane capable of being released during storage. Although this was a cargo requiring particular carriage requirements and precautions, it had not been properly declared or labelled as such by the shipper.
Ship owners have always faced the possibility of shippers presenting goods that are unsafe for sea carriage. It is an established principle in maritime law as enshrined in the Hague Visby Rules that a shipper is under a duty not to load dangerous goods without the carriers knowledge and consent. The master of a ship cannot be an expert in this respect and his practical ability to assess the safety of a commodity is heavily reliant upon its description as furnished by the shipper and its apparent external markings and condition.
If a fire breaks out at sea, the crew do not have the option of simply evacuating the building and waiting for the fire brigade to turn up.
Shipping cargo in closed containers, which may be stuffed at locations remote from sea ports well beyond the control of the carrier means that the master is as dependent as ever upon the accuracy of the cargo description.
The IMDG Code
All dangerous goods must be carried in accordance with the provisions of the International Maritime Dangerous Goods (IMDG) Code, being a comprehensive set of globally accepted rules that enables packaged dangerous goods to be carried safely by sea. As around 10% of all container cargoes constitute dangerous goods, virtually all container ship services fall within the scope of the Code. The Code requires the shipper to provide a description of the product and classification of any hazards such as toxicity or flammability. It sets limits on the type and size of packaging, specifies warning marks and labels, establishes rules for co-loading in one container and describes a system of documentation that requires shippers and packers to certify in writing that they have followed the rules of the Code. Additionally, there are provisions for correct stowage and emergency instructions for dealing with dangerous goods incidents on board ship. The IMDG Code enables the carriage of dangerous goods to be acceptable under managed risk conditions and, provided the ship is fully aware of the hazard, the packaging is adequate and intact and the stowage and segregation is carried out in accordance with the Code, the ship should be able to deal with an unexpected incident.
Why do incidents occur?
It is not usually the product itself but the failure to comply with the IMDG Code that causes incidents. Calcium hypochlorite, has a known history of causing serious incidents on board ships but is by no means the only cargo which has an unenviable reputation. The following factors contribute, either individually or in combination to cause incidents:
• Mis-declaration or non-declaration by shippers
• Quality and selection of packaging
• Provision and accuracy of documentation and labelling
• Professionalism of the container packing process
• Human factors – regional, cultural and company attitudes to good practice and compliance
• Unchecked irregularities in the product production process
• Mis-handling or dropping containers
A shipper may mis-declare dangerous goods either as a deliberate attempt to deceive or out of ignorance. An intentional mis-declaration by way of describing the cargo as a product which would ordinarily be considered harmless may be made to avoid additional freight charges or the more strict carriage requirements prescribed in the IMDG Code.
Analysis of data captured by CINS over the period 2013- 2014 indicates that 27% of incidents in terms of detected causation were attributable to cargo being mis-declared, second only to poor packaging (CINS membership includes almost 70% of the global container slot capacity).
The failure of shippers to properly declare dangerous goods is a continuing challenge for ship owners and has been a significant contributory factor in a number of high profile shipping casualties involving loss of life and severe structural damage, not to mention numerous lower intensity incidents and near misses. Worryingly, the IG Clubs have in recent years observed an apparent increase in container fires involving calcium hypochlorite which, in the majority of cases was found by investigation to have been mis- declared by shippers.
This is a chemical used extensively for purifying water supplies, as a disinfectant in swimming pools and as bleaching agent, carried as a white or yellowish solid in powder, granule or tablet form. Calcium hypochlorite is an oxidizing agent and is designated a Class 5.1 oxidiser in the IMDG Code. However, it is also unstable and undergoes exothermic decomposition at elevated temperatures, releasing chlorine, oxygen and heat or in the presence of impurities such as powdered metals or certain organic compounds. The rate of decomposition increases with temperature and is exacerbated where heat is not able to escape from within the material. The release of heat and oxygen in a self-accelerating reaction has resulted in serious fires and explosions, with the oxygen sustaining and intensifying any fire already caused by the decomposition reaction. The release of toxic gaseous chlorine is also an additional hazard to personnel.
There are varying descriptions for calcium hypochlorite with corresponding separate UN numbers as listed in the IMDG Code. However, calcium hypochlorite may be mis- declared as calcium chloride and other names encountered have included BK Powder, bleaching powder, CCH, disinfectant, Hy-chlor, Chloride of lime or Chlorinated lime. It is a requirement of the IMDG Code that cargoes are declared by their “Proper Shipping Name”, to combat issues of mis-declaration. Calcium hypochlorite is a Proper Shipping Name and as such should only be carried under that name with the appropriate UN number.
The new guidelines for the carriage of calcium hypochlorite in containers are the result of working groups set up by the IG Clubs and CINS members sharing their views and experience and undertaking a thorough review of the previous FAQ’s produced by the IG Clubs in 2010. The guidelines can essentially be considered “IMDG Code plus precautions” in that they include selected provisions from the IMDG Code plus additional precautions consistent with advice from consulting scientists. It is hoped that these new guidelines will be seen as providing a clearer and more logical step by step guidance from issues surrounding cargo hazards, categorisation under the IMDG Code, container selection, container packing and stowage on board ship.