someone dips their box boards in this green stuff. (copper napalate with diesel fuel)
A paper on the relative safety of copper naphthenate is available: http://18.104.22.168/documnts/pdf1984/kalni84a.pdf
Less than 1 ppm of Cu is added to honey and wax using the Cu preservative. The paper does caution on using fuel oil as the diluting agent, as it does migrate into the hive. Paper is older (in that Penta and other bad things were still on the market), but appears to be very responsibly researched.
My boxes are highly rot-resistant redwood and latex. (Redwood fence boards converted to mediums)
ya from the article: "Few, if any, adverse findings resulted from treatments
of beehives with (1) a preservative-free water-repellent
solution, (2) copper naphthenate, (3) copper 8-
quinolinolate, and (4) ACC. Winter survival with these
treatments was better than or comparable to that in controls. Of these four treatments, only copper naphthenate
gave a slight increase in copper content of honey (less than
WOW! The paper referenced was written in 1984....That's nearly 30 years ago...Personally, not sure I would put a whole lot of stock in it!
I did a little research on copper naphthenate since I had a friend that was using it to treat his equipment and it struck me as a bad idea. A fairly quick search lead me to a couple of interesting facts. First, I found out that it's against the law to use it to treat bee equipment in the State of Alabama. Second, I read about some bee guru that had published a book or paper on raising bees around 1994 in which he suggested treating wooden ware with copper naphthenate. He later said if he could go back and change one thing about that publication, it would be to remove that recommendation. He said unfortunately many people still use it as a reference but the practice has since been proven to be bad for the bees and something that he would no longer recommend.
I didn't dig much further...those two pieces of info were enough for me to confirm my initial skepticism on the practice...