Is it permissible to smoke and pray in a prayer room designated in the office, but some colleagues do not adhere to that and smoke in it?

A prayer room (musalla) in a workplace does not take the ruling of a mosque unless a general call to prayer is made in it. The difference between them is that a mosque is generally designated for prayer and is an inalienable endowment (waqf) that cannot be sold. As for a musalla, it can be abandoned or sold. The rulings of a mosque differ from those of a musalla: a mosque requires a "greeting of the mosque" (tahiyyat al-masjid), a menstruating woman or someone in a state of major ritual impurity (junub) may not remain in it except with ablution, and buying and selling are not permitted in it, unlike a musalla. Smoking is forbidden whether inside or outside a musalla, and prayer areas must be maintained and kept free from cigarette effects. Prayer is valid in a place where cigarettes are smoked or their remains are discarded, as these are not ritually impure. There is no objection to taking surplus carpets from a mosque and placing them in a musalla, provided that they remain an endowment solely for prayer.