Lawrence,
As secretary of the Regulatory Toxicology section of the Netherlands Society
of Toxicology I am interested in the level of (dis)agreement on this issue.
Therefore, I reply to your question via the Newsgroup rather than to you
personally. I am looking forward to other reactions!
Here is my opinion.
I tend to agree with your suggestion to apply a safety factor between 100
and 300 in this case. Firstly, because apparently there is no NOAEL here
(you based the M.O.S. on the LOEL). Secondly, because the mechanism by which
the compound exerts its non-genotoxic carcinogenic action seems to be
unknown (the finding that the tumours were benign - really? carcinoma's??? -
is insufficient).
Neglecting any route-to-route extrapolations (if necessary) these two
factors lead me to a substantially higher safety factor for workers than the
usual 30, based on an established NOAEL.
Regards,
Peter
Weterings Consultancy
Iepenlaan 16
5248 AK Rosmalen
The Netherlands
Tel/Fax: +31-(0)73 5219877
E-mail : weterin at knoware.nl
