Anti-fouling paints applied to hulls contain organometallic chemicals that are, by design, toxic to marine life. This is to prevent algae and molusk to attach t

Anti-fouling paints applied to hulls contain organometallic chemicals that are, by design, toxic to marine life. This is to prevent algae and molusk to attach to the hull, slowing the boat over time and requiring extensive cleanup. You can imagine the effect these paints have when they chip off.