All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
A man should not work in a mixed environment. However, if he cannot avoid but to work with women in a mixed environment, then he must adhere to the commands of Allaah on him, such as lowering his gaze and not being in seclusion with women unless she happens to be a Mahram.
A man is allowed to speak with his female colleague only when necessary, to discuss work-related matters, or to enjoin her to do a good deed or forbid her from doing evil.
Allaah Knows best.