Under the heading of all you never need to know about the red dye in diesel fuel, here it is. This class of dyes is not soluble in water, so it won't taint the water that is collecting in your diesel tank. This class contains many forms, other colors of which are used in other countries for similar purposes. http://en.wikipedia.org/wiki/Solvent_Red_26 Mike _____________________________________ Capt. Mike Maurice Beaverton Oregon(Near Portland)