I was gone for several hours, but back now, but anyhow I was going
to say what Heimdallr said. My Tobacco supplier said that nothing was
added - just dry hanging and "naturally grown". But do we trust what
he says? Well... I cannot verify this definitively, have no idea where
exactly the tobacco is grown, what soil type it was grown in, nor if the
tobacco seed itself is not tampered (GMA) with or not. I guess in this
case, one puts his or her life in the hands of one's supplier? Hmm...
Personally, I have not gotten sick from the tobacco mix of 1/4th black
cavendish with 3/4th mild burley approx., aromatic, mild overall. The cost
is $2.98 per oz or $76.00 per 2lb discounted, and bought locally. Depending
on the pipe used, the tobacco can last me .85/1 lb / month so it is about $38/lb/mo.
I have found that if the pipe is not kept clear of tar or cleaned often enough,
then you can get build up of tar/krap, which is nasty tasting and can cause
quite a buzz sensation for several hours. I keep a cooled pipe clean with hot
water to get the tar out, then let it cool and to completely dry out. That is why
one has more than one pipe so while one is being cleaned and dried out, use
the other.
{added} I forgot to mention, that I had to try different types of pipe tobacco
before I settled on my current one. Some PT were just too strong, over powering,
or had awful taste, or gave too much of a buzz (tar concentration?), or made me
somewhat sick. I guess your mileage may differ... perhaps try different ones from
different suppliers, different locations, different continents, and so on? I wonder
where "black cavendish" actually comes from despite the innocuous name used...