In 2010, 44 seafarers died in three separate casualties involving the shipment of cargoes which liquefied
The shipment of bulk ore and concentrates cargo with too high a moisture content for safe transportation is a perennial problem and can have tragic consequences. In late 2010, 44 seafarers died in three separate casualties involving the shipment of cargoes which (probably) liquefied. Quite apart from the human cost, the financial cost to shipping runs into hundreds of millions of dollars every year.
In the first part of three articles, we examine what cargo liquefaction is, why the problem can arise after shipment, and we highlight steps that can be taken to try to minimise the consequences. The second article in the series from Norton Rose Australia’s Dimity Maybury and Melissa Tang will examine a significant difference of international opinion on regulatory requirements for carriage of cargoes which may liquefy. The final article (to follow in a later edition) will consider some of the complex legal issues arising out of the carriage of bulk cargoes which are prone to liquefy.
What is liquefaction?
All bulk ore and concentrate cargoes are likely to have some moisture content. These cargoes are often open-cast mined, sometimes using water-jetting. They are frequently stored in the open, and in areas prone to heavy rains, prior to shipment, thereby accumulating further moisture. Some cargoes are shipped only in the dry season, but that is no guarantee of safety; a cargo does not have to be obviously wet for it to be prone to liquefy.
Bulk mineral ore and concentrates cargoes are made up of fine granular particles. There is a tiny space between each of the particles. That space is filled with either air or water. If the amount of water in these spaces within the cargo is low enough the frictional force between the grains will be sufficient to maintain the cargo in a solid state. However if the moisture content of the cargo reaches a specific level, known as the flow moisture point (FMP), the frictional force will be lost and the cargo will behave as if it were a liquid. In these circumstances it will flow freely.
During a sea voyage, the weight of cargo coupled with vibration caused by engines or machinery or the motion of a vessel at sea, particularly in heavy weather, compresses whatever water there is between the fine granular particles. That water is forced out of the spaces between the particles and can flow freely on top of, or between, the particles. When this occurs there can be either a free-surface effect or the whole cargo behaves as if it were liquid. As a result of liquefaction, carrying vessels may suddenly lose stability, and take on a list or even capsize.
Carriage of cargoes prone to liquefy
Solid bulk cargoes which are prone to liquefy are, and should be capable of being, carried safely. P&I Clubs have been issuing circulars on liquefaction for over 20 years (for example the IMO‘s Bulk Cargo Code has been around since 1981).
Currently the International Maritime Solid Bulk Cargoes Code (IMSBC Code) contains the latest internationally agreed requirements for the safe stowage and shipment of solid bulk cargoes. The IMSBC Codehas mandatory application under the Safety of Life at Sea 1974 Convention as from 1 January 2011.
Cargoes are split into three types (broader details of which are given in Norton Rose Australia’s companion article), namely those which may liquefy if shipped with a moisture content higher than their Transportable Moisture Limit (TML) (Class A), those which possess chemical hazards (Class B) and cargoes which are not Class A or Class B (Class C). Cargoes which are known to have a propensity to liquefy are listed by their Bulk Cargo Shipping Name (BCSN) in Appendix 1 to the ISMBC Code, but cargoes not listed are still covered by the Code.
Class A cargoes can be carried only where the moisture content of the cargo is less than its TML. The TML is set at 90 per cent of the FMP. The ship is entitled to demand, and the shipper must supply, accurate details of the cargo’s moisture content and FMP. The FMP has to be obtained by laboratory testing and reference to tables for that the type of cargo being shipped.
Vessels are required to carry a Document of Compliance issued by the relevant Flag State indicating which classes of cargo the vessel is suitable to carry, and any conditions of carriage which are imposed by the flag state. It is common for the certificates issued for vessels which have not been specifically constructed or fitted for the carriage of cargoes which may liquefy to state that the vessel is designated only to carry cargoes with a moisture content not in excess of the TML.
So why do the casualties still occur?
The answer is probably a mixture of lack of understanding of the problem, and inadvertent or, occasionally, deliberate misrepresentation of the true nature of the cargo by shippers and others.
From our experience of investigating liquefaction casualties and dealing with the legal and insurance issues that result we know that not every Master or Chief Officer is aware of the problem or of the simple “can” or “shake” test that can be performed to check for the risk of cargo liquefaction, despite the test being described in “Thomas on Stowage” and the IMSBC Code.
Masters are often not aware of what information they are entitled to receive from shippers under the IMSBC Code; nor are they fully aware of their rights under international carriage of goods conventions to reject or land unsafe cargo. There can be a mistaken assumption that only Class A cargoes present a liquefaction risk. In rare cases, Masters seem to abrogate all responsibility for checking whether or not the cargo being loaded on board is safe.
This is not to suggest that the problem is all one way. It is still common for shippers and charterers to use trade names rather than the BCSN. Certificates of moisture content and TML may be inaccurate. It could be that FMP and moisture tests were done at the mine, prior to storage in the open, or on unrepresentative samples, or were not done in accordance with IMSBC Code procedures, or (on rare occasions) have simply been made up. Unfortunately, not every survey certificate can be trusted to be accurate or representative.
What might be done in practical terms?
The IMO’s Maritime Safety Sub-committee on Dangerous Goods, Solid Cargoes and Containers will meet in September 2011 to consider proposals to develop a scheme for ensuring reliable independent sampling, testing and certification of cargoes and enhancing education for ship and shore personnel.
The Italian classification society, RINA, has suggested the fitting of strong longitudinal bulkheads under the hatch coamings to port and starboard in alternate holds, and only loading in the space under the hatches. This would reduce the area within which a cargo can flow or suffer a free surface effect.
The International Group of P&I Clubs has recently published its suggested Solid Bulk Cargo Clause for use in charterparties. This is a lengthy and complicated clause which re-states, and perhaps enhances, rights that the carrier has under international conventions and seeks to shift all responsibility and liability for carriage of solid bulk cargoes onto the charterer. Transferring liability is one thing but in itself it does not prevent the problem occurring. In this regard the Solid Bulk Cargo Clause includes the sensible practical suggestion that certificates stating moisture content, TML and FMP of the cargo be provided by a laboratory approved in advance by the owner.
These measures may take time to implement or be impractical in some situations. While increased regulation, alterations to ship design and use of contractual arrangements can all have a part to play, other commonsense and straightforward steps should not be overlooked.
Owners who charter their ships to carry bulk cargoes need to ensure that their Masters and Chief Officers understand the problem of liquefaction as well as the classification of cargoes, and their rights and obligations under the IMSBC Code, the need to perform visual inspections, and the simple “shake” or “can” test that can be done to check before loading whether a cargo is prone to liquefaction, whatever the documentation provided might say. Masters and officers also need to understand that liquefaction can be a risk for all fine particled bulk cargoes, whether or not listed as Class A, and to recognise the importance of level trimming of such cargoes. Owners might also question whether the process of engaging Masters and Chief Officers sufficiently tests their knowledge of the risk of liquefaction and how to deal with it? And while a tick-box exercise is no substitute for the proper exercise of skilled judgment, those on board might benefit if the onshore operations departments provided more detailed or specific loading checklists in relation to liquefaction risks.
It may not be possible to get agreement to the Solid Bulk Cargo Clause, and even if this is included it may conflict or contradict with other provisions in the charter. Those in owners’ chartering departments also need to understand the shipper’s obligation to declare the BCSN and to query the use of trade names, which may (innocently or otherwise) be misleading. Making detailed enquiries prior to fixing charters as to how the cargo has been mined and how it is, or will be, stored and who will undertake sampling and testing, might enable a better assessment of whether or not the cargo can, or should, be carried and, if so, on what terms.
As we shall examine in a later article, charterers, shippers and receivers can each have legal responsibility and potentially unlimited liability for the shipment of dangerous cargoes, and the law does not limit “dangerous” cargoes to those listed in the International Maritime Organisation’s Dangerous Goods Code. Therefore charterers, shippers and receivers may need to tighten up their own procedures and their sale contract requirements to ensure not only that they are provided with proper and accurate documentation, in order to fulfil their IMSBC Code obligations to the carrier but also that they take steps to verify the information, rather than simply passing on information or relying upon the carrier to carry out tests later. Hull, cargo and liability insurers could also perhaps take a look at whether suitable policy conditions (such as sampling and testing by a laboratory approved by underwriters or owners) or policy exclusions might also assist the industry in improving loss records in this area.
Only with concerted effort and the taking of practical steps by all involved in the sale, carriage and insurance of bulk cargoes will it be possible to tackle the problems of cargo liquefaction at sea. Debate continues at IMO, but as our next article shows, there is a divergence of opinion as to what the regulations actually mean – an issue which causes practical difficulties for both owners and charterers.
John Liberopoulos & David McKie
Lawyers at Norton Rose Group
Above article is part of October Newsletter – Legalseas by Norton Rose.
For more information, click at the following link
http://www.nortonrose.com/knowledge/publications/56740/shipping-newsletter-legalseas
