The responses of the grand maraji’ to your question are as follows:

The office of the Grand Ayatullah Sistani (may Allah prolong his life):

1. Alcohol is intoxicating and its consumption impermissible.

2. It is haram.

3. If it has a great harm, even due to it being addictive, it is haram, and even if it doesn’t have such a harm, as per obligatory precaution, it is still haram.

4. If it isn't khamr  [wine or liquor made from grapes] and it constitutes one or two percent of the entire combination, it is permissible.

The office of the Grand Ayatullah Makarim Shirazi (may Allah prolong his life):

1. Industrial and medical alcohol which one does not know whether it comes from an intoxicating liquid, is pak. The same goes for the alcohol used in cologne, sprays and medicine which contain industrial or medical alcohol.

Please do note that those alcohols that aren't essentially consumable or are poisonous aren't najis, but whenever they are diluted to become beverages and intoxicating, their consumption will be haram and as per precaution, they will have the ruling of being najis.

2. Liquor and any liquid that intoxicates the person is najis as per obligatory precaution, but substances like Hashish or ‘Bang’ which are narcotic and aren't liquid in essence are pak, even when mixed with water and made into liquid, although their consumption nonetheless is still haram.

3. Due to their many harms verified by the experts, smoking cigarettes and all other types of tobacco products is haram.

4. If medical alcohol is used in it and in present circumstances, it isn't an intoxicating liquid, it isn't problematic.

The office of the Grand Ayatullah Saafi Golpaygani (may Allah prolong his life):

1. In the case of it being intoxicating, it is haram.

2. The consumption of anything intoxicating and inebriating is impermissible.

3. Intoxication and inebriation is impermissible.

4. Just because something is prescribed doesn’t make it permissible; no matter how little or how much something has an intoxicant substance in it, the ruling is the same.

Relevant questions:

Question 9102 (site: en9096) (The tarahat and permissibility of industrial alcohol).

Question 20509 (site: en19738) (The ingredients of alcohol and gelatin in candy).

Question 7828 (site: en7832) (Serving alcoholic beverages in a restaurant).