The awareness of the harmful environmental effects of organotin compounds gradually grew in the late 1980s. Scientific studies have shown that organotin compounds, particularly TBT, used as anti-fouling systems on ships pose a substantial risk of adverse impacts on ecologically and economically important marine organisms. The IMO held a diplomatic conference on the control of harmful anti-fouling systems for ships from 1 to 5 October 2001, which adopted the International Convention on the Control of Harmful Anti-fouling Systems for Ships 2001. This convention provides rules to ban the use of organotin based anti-fouling systems – TBT – which are harmful to the marine environment and provides a mechanism through which other harmful anti-fouling systems may be banned or regulated in the future on a global basis.