Ruling on selling perfumes that contain harmful substances

If it is not proven (and it is not thought most likely) that these perfumes are harmful, then there is nothing wrong with buying and selling them, or using them, because the basic principle is that this is permissible, and there is no evidence or reason to make us shift from this basic principle. 

But if it is proven that these perfumes are harmful, then it is prohibited to use them and perfume oneself with them. 

Based on what is well-known from the texts and basic aims of Islam, anything that causes harm to one’s religious commitment or physical well-being, whether it is food, drink, oil, perfume or the like, it is prohibited for the individual to use it or deal in it. Allah, may He be exalted, says (interpretation of the meaning): “and make not your own hands contribute to (your) destruction” [al-Baqarah 2:195]. 

It is not permissible for the Muslim to sell these harmful perfumes, because that is causing harm to others, which is haraam, because the Prophet (blessings and peace of Allah be upon him) said: “There should be neither harm nor reciprocating harm.” Narrated by al-Haakim (2/57-58). He said: Its isnaad is saheeh according to the conditions of Muslim. It was also classed as saheeh by al-Albaani in Silsilat al-Ahaadeeth as-Saheehah (1/498). 

If the purchaser is happy to buy these perfumes because he wants to imitate women, then it is not permissible to sell it to him in this case either, because that is helping him to imitate women, which is a major sin. The Messenger of Allah (blessings and peace of Allah be upon him) cursed men who imitate women and women who imitate men. Narrated by al-Bukhaari (5435). 

Secondly: 

With regard to finding out from the supplier about the ingredients of these perfumes, if there is certainty that these perfumes are harmful, then there is no need to ask about that in that case, because what you must do is refrain from using them, and asking about it will not change the facts of the matter at all. But if there is some doubt about the harmful effects of these perfumes and the matter has not reached the degree of certainty, then you should ask to find out the facts in this case. The stronger the suspicions and doubts, the more important it is to ask. 

This applies if the supplier is going to the tell the truth. But if he is going to lie in order to promote his own product, then asking this question will not benefit the questioner at all. 

And Allah knows best.