Everyone agrees that ethanol is corrosive and can attack elastomers not designed to withstand it. I’ll comment on the “10% to 40%” question. The EPA just recently approved 15% for over the road moror vehicle use. However, ethanol use is not mandated, only approved. We’ll see whether the gasoline industry begins making the switch. My own feeling is that nobody will buy it so nobody will sell it. Some may try, but when they lose customers and begin getting complainst they’ll go back to 10%…or 0%.
IMHO ethanol is a farce anyway.