Although I am not familiar with the product "Dragnet", I am reasonably
familiar with the active ingredient, permethrin.  I find it interesting
that your exterminator suggests that permethrin is not safe for animals
(although I do not know the concentrations that the product contains),
as permethrin is also the active ingredient in the human lice cure "Nix",
and in the topical reptile miticide "Provent-a-Mite" (perhaps not
surprisingly, it has been reported that the woman that developed "Nix
will not use it on her own family, and a number of reptile deaths have
been linked to use of "Provent-a-Mite").
 
I am assuming that the Dragnet is being applied via a spray.....although
I am unfamiliar with industry recommendations as to contact with treated
areas, I do know that permethrin products do have a certain amount of
activity for up to ten days after application.  I would consider
steam-cleaning your carpet furniture prior to letting your ferrets on
it, although, provided a reasonable amount of time has passed since
application of the Dragnet, I would think that your home would be within
'safe' parameters even without steam-cleaning.
 
G. A. Christian Bilou
[Posted in FML issue 3541]