Quoting from the UK Department for the Environment Food and Rural Affairs 
booklet 'Managing Varroa' re Oxalic acid
Quote
Ideally needs broodless conditions, 90% average efficacy possible, sugarless 
solutions have poor efficacy,DANGER OF SIGNIFICANT COLONY WEAKENING (my 
emphasis), more scientific trials needed....
End Quote
From the above I would not hesitate to suggest that oxalic acid could have 
some toxicity to bees.
(toxicity does not necessarily mean kill)
Ruary
----- Original Message ----- 
> I also wondered Ruary but figured I would get a storm of emails if I even
> suggested the term toxic as used was referring to bees. I have seen OA 
> used
> for over a decade in many areas of the U.S.. As Medhat pointed out only 
> when
> the wrong mixture has been used has the OA been toxic to the bees.

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