Most new stainless is made up of over 80% recycled stainless. The material is the ultimate recyclable material and will not degrade during it lifetime. In fact, after 30 years or more should you which to recycle your tank you will be welcomed by metal recyclers , no other tank has this feature. Other tank choices such as polyethylene or plastic coated steel (Colourbond Aquaplate) are much less recyclable at end life and may find there way in land fill. Over the life span of the tank your choice of stainless steel will have the lowest carbon footprint. For further reading see