Bevex, an artificial sweetener used only in soft drinks, is carcinogenic for mice, but only when it is consumed in very large quantities  To ingest an amount of Bevex equivalent to the amount fed to the mice in the relevant studies, a person would have, to drink 25 cans of Bevex-sweetened soft drinks per day
For that reason, Bevex is in fact safe for people
Cancer from carcinogenic substances develops more slowly in mice than it does in people.