Randy Oliver wrote:
>> 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.

Interesting stuff, but it seems that there is more than one TLV:
TLV-TWA Threshold Limit Value - Time-Weighted Average: The time-weighted 
average concentration for a normal 8 hour work day and a 40 hour work week, 
to which nearly all workers may be repeatedly exposed, day after day, 
without adverse effect.

TLV-STEL Threshold Limit Value - Short Term Exposure Limit: a 15 minute 
time-weighted average exposure which should not be exceeded at any time 
during a work day even if the 8 hr TWA is within the TLV. Exposures at the 
STEL should not be repeated more than 4 times a day and there should be at 
least 60 minutes between successive exposures at the STEL.

TLV-C Threshold Limit Value - Ceiling: the concentration that should not be 
exceeded during any part of the working exposure.

So which of these does the 1mg/cubic metre fall into - and how would we know 
the value to which the beekeeper was being exposed?  Weather conditions at 
the time could cause very large variations, even where a standard dose per 
colony is being applied.

Peter Edwards
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www.stratford-upon-avon.freeserve.co.uk/ 

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