Why is it that UK detergents say "bio" or "non-bio" on the labels?

Question

I understand that these labels mean there's some kind of difference in the detergent formulation. But why is is that you don't see these labels in the US?

Answer 1

My box of Cheer laundry detergent says, "Ingredients include biodegradable surfactants and enzymes." So the information is on the label.

Of course, biodegradable means that something will break down in nature.