No one is selling 70% ethanol as an antiseptic, it's isopropyl alcohol. Those additives in ethanol not intended for consumption are 8 parts acetone and 1.5 parts methyl isobutyl ketone to 100 parts ethanol. There are some rare ethanol based rubbing alcohols sold but the vast majority is isopropyl because it's not just denatured with bitterants, they add toxic substances as well.

Here's the actual formula they have to use that's enshrined in the law. https://www.law.cornell.edu/cfr/text/27/21.49