IME with industrial alcohols, different entities will have different amounts of leeway and with ethanol in particular in the US there are some of the most bizarre regulations.
Natural agricultural ethanol or distilled beverage grade ethanol is highly taxable by numerous agressive collectors so major obstacles to industrial use have long been overcome by _denaturing_ the otherwise natural grain alcohol, by adding a poisonous or disagreeable substance to discourage consumption and therefore avoiding any beverage taxes.
Different denaturants are expected to be used for different end uses of the ethanol, but fundamentally anything (on the list) will do since the primary motivation is taxation/regulatory not function/purpose.
Here is the list, some in the Specially Denatured Alcohol (SDA) category are also approved for personal use by the FDA:
https://www.law.cornell.edu/cfr/text/27/21.151
Notice that using plain gasoline (leaded) as well as unleaded for denaturant will introduce some benzene to the ethanol since gasoline almost always contains at least a fraction of a percent benzene naturally.
Also, the alternative _High Octane Denaturant Blend_ for CDA20 would be just fine having up to 1.1 percent benzene:
https://www.law.cornell.edu/cfr/text/27/21.112-T3
Now the Acetaldehyde _denaturant_ that could be used to exempt an industrial alcohol from beverage tax is actually often found naturally in lower-grade less-refined agricultural ethanol, so it originates like an ordinary non-beverage solvent. Once this type material arrives in a common bulk fuel terminal, often it will then be further denatured with a few percent of some fairly high-octane gasoline, carefully measured from a nearby tank. Since the Fuel-Grade ethanol they will be distributing has a maximum 2.5 percent additional denaturant allowed, and the gasoline is lower cost per gallon than the raw ethanol.
The final fuel grade ethanol spec allows 0.06 percent benzene or about 600 ppm:
http://www.cvec.com/wp-content/uploads/2018/03/PRODUCT-DATA-...
Notice that anhydrous ethanol is not a consideration along this supply chain, up to 1 percent water is allowed in the ethanol that is going to be blended with gasoline for clean-air purposes. Also I was the one who originally proposed the use of method E-1064 for this precision measurement when we were drafting this specification to begin with.
Seems to me like some sanitizer formulators are using fuel-grade ethanol sometimes whether they know it or not, or maybe trying to avoid mere automotive products and using a more carefully specified SDA material.
But a version of SDA28A consisting of highly purified ethanol having only pure Heptane as denaturant could be obtained completely benzene-free, while a different version of SDA28A containing conventional gasoline as denaturant would be expected to contain both benzene and lead.