that the company's vessels are not traded down market) for at least 30 years, and at the end of their lives are scrapped. Maintaining equipment involves computerised planned maintenance systems, the upholding of clear maintenance standards, real- time monitoring of the ship by shore-based management and a comprehensive ship inspection programme. However, with the best of intentions, not all risks can be covered, as proved by the case of the Stolt Rotterdam, a chemical barge that spilled nitric acid into a German river. According to Russi, the company believes that the incident occurred due to a burst gasket or a failed valve. For the time being, he said, Stolt is no longer using that type of ship for the carriage of nitric acid, and all of the barges in the fleet have had their valves and gaskets checked. Although a company can pursue its risk management strategies in the best of faith and with a concerted effort, incidents can still occur, which leaves the door open for continuous improvement processes. Stolt-Nielsen has developed a number of improvement teams which draw on members from senior management who set overall continuous improvement objectives, manage the improvement process and ensure that the objectives are being achieved, as well as department members who provide specific input. Ultimately, charterers also have a role to play. "Shippers should use quality as the sole selection criterion for chemical tankers," said Russi.