Is working as an accountant for a company that trades in products locally forbidden but internationally permissible considered unlawful?

The basic principle concerning buying and selling is permissibility, due to the generality of Allah’s saying: "And Allah has permitted trade and forbidden interest," and the Prophet's (peace be upon him) saying: "Leave the people; Allah provides for some of them through others." However, this principle may be superseded, taking it out of the realm of permissibility, if the sale leads to harm befalling people, or if there is a recognized legitimate interest in prohibiting it. In such cases, the ruler is permitted to prohibit trading. The questioner's work in the company depends on the permissibility of selling these goods. Therefore, he should consider whether prohibiting the company serves a benefit, in which case he should refrain from working with it, or if the state is oppressive in its prohibition, in which case he is permitted to work.