Cargo contamination claims are one of the key risks the Association deals with when assisting members in the chemical tanker trade. Ensuring tanks are actually at the right level of cleanliness prior to loading is key, but it is open for debate whether exisitng testing methods are sufficient to verify the same. The Association is grateful to Guy Johnson, Director of L&I Maritime for contributing to this debate. The situation Cargo contamination claims are one of the most frequent issues the Association has to deal with for chemical tanker members, a related and equally frequent issue are disputes over the cleanliness of tanks on a vessel prior to loading. Both types of disputes come with the risk of significant claims and losses, and given the very technical nature of the subject matter it is likely that only through extensive scientific investigation it is possible to come to a view as to what the precise underlying issue may be. That means there will inevitably be significant costs and time involved in the investigation, analysis and debate over the evidence. One particular feature in these disputes is the methodology by which a vessel's tanks are tested for cleanliness. A common method is the wall wash inspection which means that part of the cargo tanks are "washed" with a solvent which is then analysed to see what - if any - materials can be found therein, i.e.: to check against the presence of possible contaminants in the tanks. Over time this method developed from a somewhat straight forward process, intended to demonstrate the ability to clean tanks to a certain standard, and it has now evolved into a very exacting testing regime that may be looking to check for the presence of materials in the parts per million. Whether wall washing is an effective means of checking the cleanliness of tanks, and whether it remains suitable and appropriate or whether there are acceptable alternatives is a matter of debate. A debate, however, that will have real monetary s