> There were comments adverse to using sulphur...
> While you certainly should avoid getting a lungful of the vapor,
> the resulting SO2 is permitted for use in foods....

Sulphur is the traditional method of killing bees in skeps from which
honey was to be harvested.

As far as hazard, well, I lived in Sudbury Ontario for years, and on a
day when we had an inversion, there was a blue haze everywhere.  Sulpur
dioxide.  It didn't seem to harm people much, but until they put up the
superstack and sent all that stuff up and far away, the trees around the
area were pretty stunted.

And when I worked in the Copper Cliff smelter, there were days when you
could not see across the street in the compound for SO2.  We didn't like
it much, but no one seemed to suffer any injury from it.  I also
remember walking own the converter aisle (the main street of hell) with
huge open cauldrons of sulpherous ore glowing white and spewing amazing
amounts of SO2 in the process of purification to nickle oxide.  The
fumes were drawn off the furnaces and down the aisle to the opening of
the stack by convection.  People worked in there all their lives. AFAIK,
there weren't an unusual number of respiratory ailments among them.
Toxicity was never considered a problem.

I wouldn't worry a bit about using sulphur -- unless you plan to confine
yourself in a small space with a lot of it.

allen