I've used autofuel for about 15 years now & have never seen any
contamination in it, or from it, at all. There is lots of gasahol
around here so I have to check each load with the water absorption
test to detect if there is any alcohol present, unless I can buy it at
an FBO. I assume MTBE can be smelled. It is almost universal here in
the midwest. I have metal tanks though.