All perfect praise be to Allah, The Lord of the Worlds. May His peace and blessings be upon our Prophet Muhammad and upon all of his family and companions.
There is no prohibition against working in the manufacturing and marketing of charcoal. Charcoal is a pure commodity from which benefit is derived; it is permissible according to Islamic law, and its nature is neutral. It may be used for permissible purposes, such as cooking food, heating, lighting incense, and similar uses. It may also be used for impermissible purposes, such as lighting "argileh" (waterpipes) or cooking unlawful food, such as pork. However, the sin and responsibility in such cases lie with the one who uses it for an unlawful purpose.
That said, if a specific type of charcoal is exclusively designated for unlawful use and cannot be used for anything else, then manufacturing it—as well as selling it—becomes forbidden.
In conclusion, there is no prohibition against manufacturing and selling charcoal if it can be used for lawful purposes, such as cooking, heating, and the like. However, if it is specifically designated for unlawful use only and cannot be used for anything else, then its manufacture and sale are forbidden. And Allah, the Most High, knows best.
