>>>>>I OA trickled my over wintering nucs. I killed nearly  
70% doing so. I don't think they had a cleansing flight afterward...

Wow, Mike,  that must have hurt!  I'm in Calif, and the bees have always
been able to fly when I've treated.  I'm very curious as to why you suffered
such a disaster, since we have seen nothing of the sort.

>>>>>OA in nucs is a great way to start relatively mite free colonies.
>>>>>It's also good for treating unknown swarms. 
Waldemar, we also use it when doing "shake and bake" of AFB colonies.  

Anyone, I don't know if you've checked the TLV's (threshold limit values of
vapor) of oxalic, but the vaporized gas is pretty hot stuff!  The TLV of
oxalic is 1mg/cubic meter.  For comparison, the TLV of formic acid is 9.4mg,
for acetic acid 25mg, for ammonia 17mg, chlorine gas 1.5mg, hydrogen sulfide
14mg, hydrochloric acid 7.5, benzene 1.6mg, and toluene 188mg.  I
arbitrarily listed some dangerous vapors for comparison.

If one is vaporizing 1.4g of OA per colony, and half of it vaporizes, then
you've created enough vapor to make 700 cubic meters of air dangerous
(that's about a 50ft square house!)  That's per colony treated!  

Am I being too cautious?  There have been a number of formic acid inhalation
injuries and deaths, is OA vaporization in the same risk group?  The
websites Mike referred to say it's safe, but I'm curious.  Anybody have a
better handle on just how dangerous vaporizing OA into hives on a large
scale is to the beekeeper?  Will one good accidental breath kill or
seriously harm you?

Randy Oliver

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