10 or a few more years ago, a research paper on the topic of wood
   preservatives and bee hives, was published (I don't remember where, can
   anyone help?). Perhaps there is more concern now, but as I recall, the
   conclusion was that once well dried, most of the preservatives were
   suitable for bottom board use. Paint on top of the preserved wood would
   be an added level of separation of the chemical from the bees.
 
   As indicated by the other messages, a high level of caution in this use
   is justified. I don't think use of this type of preservatives on any of
   the other interior surfaces of the hive is advisable. You might consider
   some other methods like dipping in melted wax, which are inherantly
   safer for the honey.