> A would be refilled-cartridge-seller assures me the toner
    > is carcinogenic.   Who knows.
    > One suspects this is a desperate sales ploy, but ... (Anyone know?)

Find the MSDS (Material Safety Data Sheet) for your toner cartridge.  It's
probably accessable via the printer manufacturer's web site.  These are
required to be provided, and they'll list any known-harmful ingredients,
along with at least some of the non-harmful ingredients.

>From perusing the MSDS's at work, there are a wide variety of compositions
used in toners (different coloring agents, different binders), and none of
them are known carcinogens.  The chances of a carcinogen being used as a
toner that will end up on pages that are to be handled contantly by human
hands are about zero, IMHO.  Don't eat it, don't snort it.

When seeking a replacement toner as a refill, find one with similar
ingredients listed on the MSDS...

BillW