Mary Lou wrote:

Hi all, I just want to remind you that Captan is a known carcinogen
(by the State of Florida) so be very careful not to expose yourself to
it on your skin or inhaling the dust. I used to use it very carelessly
years ago, not knowing. Now I use cinnamon in it's place most times.



Actually according to the Material Safety Data Sheet (MSDS), Florida has
some sort of knowledge that the scientific community doesn't....
http://www.greenbook.net/docs/MSDS/M37110.PDF There are far worse
things for you than this that are perfectly legal. You should see the
MSDS for table salt. Or water, for that matter. Here is a link to one
of the sheets for good old aqua pura
(http://www.bandj.com/BJMSDS/MSDS_PDF/water.pdf).

Captain is classified as a 'probable human carcinogen', based on tumor
formation in some laboratory studies (ie, not humans) and similarity to
known carcinogens. Probable carcinogen is not at all the same as 'known
human carcinogen'. Actually tumors are not necessarily a horrible thing
either, if they are not malignant (I presume they are non-malignant, or
there would be a note to that effect). No evidence of mutagenic or
teratogenic activity for this compound in laboratory studies. Oral LD50
(the dose lethal to 50% of the subjects) in rats is 5g/kg. I weigh
about 100kg. That means I'd have to (if I were a rat) eat 500 grams (a
little more than a pound) of the stuff to have a 50% chance of kicking
off. I'll take that risk.

As to care in using it, of course... But, according to the laboratory
studies, dermal(skin) toxicity in rat has an LD50 of 2g/kg (half a pound
to put me in the ground) and inhalation toxicity is 1.0mg/L (trust me,
that is pretty high too). So, I wouldn't worry too much about a little
dust. It is supposed to be an eye irritant, so don't throw it at your
face. Again, just because something is relatively non toxic doesn't
mean you should shower with it, use due caution and wear protective
gear, but don't freak out if you spill a bit of it.

So, banning it because it is a human carcinogen is not at all correct.
It is not. More accurately, if it is, it hasn't been demonstrated. It
is _likely_ to be carcinogenic in high doses, but that isn't the same
thing. It is horribly toxic to fish, however, which might be a good
enough reason to ban it. Is this a case of regulation gone too far?
Maybe. Don't ask me, I don't use Captan either. But I might like the
option if I had a million plants. Cinnamon works for me too...

Rob

--
Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a. See rule 1
3) When one has insufficient credit to purchase
more orchids, obtain more credit