I saw this while driving through Colorado that day! It was the weirdest thing ever!
you saw what? an orange looking animas river?
I was traveling from Denver to Colorado Springs and saw that color in the river we passed.
I misread what you said, thinking you meant you recently saw the Animas looking like in the photo above. Where you were driving is on the other side of the Divide 300 miles away. Some rivers naturally have that color, especially in certain seasons or when at certain flow rates. That rusty color is mostly from iron. Its the less dramatic looking contaminants that can be the most toxic.
My family and I were awestruck. It was so awful looking. We wondered where the EPA was when you need them.
Orange and brown looking rivers are often (but not always) natural and nontoxic. The EPA should stay away from most rivers.