
No, there is something called the "Delany Amendment" which makes carcinogenic
food additives illegal in any amount.  This was passed by Congress in the
1950's, before stuff like mass spectrometry became available, which increased
detectable levels of substances by a couple orders of magnitude.

This is why things like cyclamates and Red #2 were banned.  They are very
weakly carcinogenic in huge quantities in rats, so under the Act they are
banned.

This also applies to natural carcinogens.  Some of you might remember a
time back in the 1960's when root beer suddenly stopped tasting so good,
and never tasted so good again.  That was the time when safrole was banned.
This is the active flavoring ingredient in sassafras leaves.

If it were possible to market a root beer good like the old days, someone
would do it, in order to make money.  The fact that no one does it indicates
that enforcement is still in effect.