Biosok is the product to ensure you have environmentally friendly bilge water.
If you want to get rid of the oil and diesel in your bilge or under your engine, put a (Bio)sok in it! This sock breaks down fuel and oil into harmless natural products which won't harm the environment. The product gradually disappears (depending on the amount of diesel/oil it has to deal with) until eventually you are left with an empty sock, which means it's time to throw it away and get another one.