Alcohols are divided into two groups: Alcohol that is produced through chemical processes and the one produced through distillation and fermentation. Since ethanol is an industrial alcohol, we will take a look at some facts about industrial alcohol:

The truth of the matter is that industrial alcohol shares the same formula fermented alcohol has (C₂H₅OH). The difference between the two though, is that industrial alcohol isn't considered khamr, while distilled alcohol, since it comes from the distillation of khamr, might be considered khamr itself.

The common viewpoint among the ulema is that any intoxicating substance that is originally liquid is najis. The question is, does industrial alcohol fall under this category or not?

According to the common viewpoint here, it seems that industrial alcohol can't be considered an intoxicant although it is used in intoxicating drinks. The reason that it isn't considered an intoxicant isn't that they add poisonous and foul-smelling substances such as methanol to it, but because it is so dense and concentrated that if no additives are added to it, drinking even a little is poisonous, this is why this substance (industrial alcohol) isn't considered as an intoxicant by the people (urf).[1]

The verdicts of the maraje’ corroborates this matter:

Imam Khomeini: Industrial alcohol which is used for painting doors and tables and chairs and the like[2], if one isn't sure if they are produced from something[3] that is originally liquid and intoxicating, it will be pak.[4]

Zanjani: If one isn't sure whether it is intoxicating or not, then it is pak.

Fazel: ‘White Alcohol’ and medical alcohol which are pure alcohol and are used for medical purposes are pak, unless they are obtained by wine or fuqqa’; in such a case they will be najis. Also other solutions used for cleaning that have alcohol in them and are used in medical clinics are pak.

Also, industrial alcohol which is the same as ‘white alcohol’ with some poisonous additives and is used for industrial purposes is pak. Cologne and industrial substances that contain alcohol are all pak as well.

Sistani: Alcohol, whether it is industrial or medical in all of its different types is pak.

Makarem: Industrial and medical alcohol in which one doesn’t know come from something that is originally liquid and intoxicating are pak. The same goes for colognes and medicines that have a mix of medical or industrial alcohol.[5] [Also], alcohols that are inconsumable per se or are poisonous, aren't najis. But if they are diluted and become intoxicating, consuming them will be haram and they will be najis as a precaution.[6]

Conclusion: Alcohols such as ethanol and methanol which are originally poisonous and aren't consumable are pak and can be consumed if they are used in any medicine. Of course, if they are diluted to make them intoxicant and usable in wines and the like, they become haram and najis.