Good afternoon.  I am not finding any concrete documentation indicating that honey bees visit poison hemlock, nor is the honey produced dangerous.  Honey been visit many, many different plants to meet their pollen and nectar requirements.  Therefore, any chemicals they would acquire would be diluted.  Here is some further reading if you are interested:  https://cordis.europa.eu/article/id/32901-how-honeybees-avoid-toxins-in-flower-nectar

Thanks.