tributyltin compound

thumb|The structure of tributyltin oxide: the most common TBT compound used in marine paint thumb|Biofouling on the hull of a boat

Tributyltin (TBT) is an umbrella term for a class of organotin compounds that contain the group, with a prominent example being tributyltin oxide. For 40 years TBT was used as a biocide in anti-fouling paint, commonly known as bottom paint, applied to the hulls of oceangoing vessels. Bottom paint improves ship performance and durability as it reduces the rate of biofouling, the growth of organisms on the ship's hull. The TBT slowly leaches out into the marine environment where it is highly toxic toward nontarget organisms. TBT toxicity can lead to biomagnification or bioaccumulation within such nontarget organisms such as invertebrates, vertebrates, and a variety of mammals. TBT is also an obesogen. After it led to collapse of local populations of organisms, TBT was banned.