Rob makes some good points, but a few things about Captan should
be mentioned.

If memory serves, Canada was the first to raise questions about
captan some years ago. Supposedly their strawberry crop was going to
implode if it were yanked. California did the same thing; they consider it
a carcinogen under Proposition 65.

I would have to disagree with the statement that captan hasn't
formed *malignant* tumors in experimental animals; see also:

http://www.nohsc.gov.au/OHSInformati.../az/Captan.htm

"A more recent review of two studies (the NCI Captan Rat and Mouse
Studies) on the carcinogenicity of the fungicide captan was based on
examination of the histological sections. The results and conclusions
indicate that captan is highly carcinogenic in rats and mice. Neoplasms at
all sites, as well as malignant neoplasms, were increased in both low- and
high-dose captan-treated male and female rats." Still, that's not enough
to convince IARC that it's a human carcinogen; I've waded through IARC
standards, working with chromium compounds, and their bar is set pretty
darned high. By the time IARC says it's a human carcinogen, you can bet
the house they've done their homework.

However, the EPA only classifies it as "B2," or "probable human
carcinogen." Their full report is at:

www.epa.gov/oppsrrd1/REDs/0120red.pdf

A quick review of the bibliography shows that only two studies
into the carcinogenic properties of captan in the bibliography are less
than a decade old.

Is it a strong carcinogen? No. I suspect the main reasons for
concern are that people exposed to large quantities of it- field
application and harvesting- may be subject to its effects, which also may
include birth defects. How well these high test concentrations (300 mg/kg)
in a small sample set of animals compares with much lower doses in a human
population of millions are poorly quantified. The way the EPA looks at it
is to examine how many strawberries (for example) a person might consume
if they had a particular fondness for the drupe. And would consuming
pounds and pounds of captan-treated strawberries every month cause more
than a one-in-a-million lifetime chance of cancer?

I'd prefer to err on the side of safety, since there has
historically been a long record of safety testing paid for by the company
that manufactures these compounds that later demonstrate more ominous
effects in studies without the same financial controls at the reins. In
the "good old days," captan salesmen used to consume a spoonful of their
product to demonstrate its safety. No longer.

The e-mail address in the header doesn't work. Sorry.


-AJHicks
Chandler, AZ