Published: 1 August 2015

This article continues our series highlighting good practices that can be shared with Members and looks at contamination claims from tankers.

We have recently reviewed a number of tanker contamination claims with a total value of USD 4 million.  In this article we will highlight some common causes of these claims which can be traced to failures in shore side and shipboard  management.

In the conclusion,  we will look at some recommended best practices on board the ship before loading cargo and also suggest preventative measures that can be taken once the cargo is on board the ship  in order to reduce exposure to these claims.


The claims investigated revealed that 50% of dirty oil claims and 44% of clean/chemical oil claims originated from the terminal or were otherwise pre-existing.  The most common contaminant is water delivered with the cargo.  Fresh water derived from the manufacturing process can settle in a shore tank during storage or may already be present in the shore lines.

The findings from our investigations showed that cargo was also off spec before reaching the ship in respect of the sulphur content or the flash point.  Other contaminants (which might have originated from lines ashore or shore tanks) include rust, suspended matter or contaminants from previous cargoes in the shore line.

Ship staff must remain vigilant to ensure that the correct method of testing is applied to the cargo i.e. for determining water content in high density cargoes, using ullage temperature interface detectors (UTI) rather than colour cut water finding paste could be more effective.


Due to the range of cargoes being carried, particularly chemical cargoes, the investigations showed how important it is to check that the tank coating is suitable for the booked cargo and the crew should verify this with the manufacturers’ tank coating cargo resistance lists.

In one incident the coating specification included a specified number of days that a cargo could be stored at a higher temperature.  The time limit was ignored and the tank coating peeled off and contaminated the cargo.

Other problems have included cargo discoloration and tank cleaning issues caused as a result of the nature and condition of the coating.


Cargo tanks and lines must be carefully prepared to load the nominated cargoes.  The claims review revealed the following issues:

  1. Tanks and lines contaminated with cleaning media, including water
  2. Water being found in the tanks and lines which could come from the cargo system, inert gas, leaking heating coils or via the hatches and tank lids
  3. Lines not  being cleared between products
  4. Previous cargo residue or vapour remaining inside the hose or line
  5. The vapours from one grade of cargo can put another grade of cargo out of specification if the vapour lines of common inert gas systems are not segregated


The claims review revealed the following:

  1. Inadequate tank condition and structural deficiencies, including bulkhead cracks
  2. Rust in the tank or generally poor tank condition due to lack of effective maintenance
  3. Tank coating damaged due to poor preparation during application and by not curing properly. Failure to repair this in time could lead to previous cargo becoming ingrained into the coating and contaminating the next cargo
  4. Valve leakage, which could lead to cross contamination between grades of cargo


Sampling is extremely important  when  monitoring the quality of products carried on board the ship and the methodology employed to extract the sample and to store it may be vital in handling and rejecting spurious contamination claims.

Sampling varies with the cargo type but must always be representative of the product and samples must be taken using appropriate equipment.

Bottles and equipment should be clean and suitable for the cargo.  Ships officers should check how the shippers’ surveyors are taking samples and note protest if any malpractices are noted i.e. using dirty / rusty equipment.  Comparisons and tests should be conducted using the same standard and the agreement between the shipper and the consignee should specify the test method.  In one case, the shore tank sample was analysed at the discharge port using ASTM method D5443.  However, the analysis carried out at the shipper’s lab used ASTM method D2360.  Clearly, the use of two different tests meant that the results could not be directly compared.

Sample bottles and seal numbers should be noted and a sample log kept up to date.  All bottles should be labelled, sealed, witnessed and countersigned.  Samples should be stored securely and for a length of time which complies with company procedures

In case of any off spec allegation or notification, it is crucial to inform both the shipper and the consignee, without delay, to retain all their sample bottles until the issue is satisfactorily resolved.


Most tanker claims can be prevented by effective pre-planning and preparation of the tanks, and by ensuring that all relevant ship staff are aware of potential hazards.

In product and chemical tankers, ship staff should carry out regular inspections, particularly of areas that are not readily visible, i.e. bell mouth, for signs of discoloration, bubbles or flaking paint.  Excessive corrosion may also be visible in the adjacent double bottom or side tanks.

An effective cargo plan, an observant cargo watch and appropriate sampling procedures can help Members to reject allegations of contamination by the ship.