Being a Group 1 carcinogen, let's analyze it with other carcinogens in the same group: is there such a thing as "won't actually harm you" amounts of asbestos? What about "won't actually harm you" exposure to ionizing radiation?
We don't know which DNA damage will turn into cancer, but each exposure to a group 1 carcinogen is another lotto ticket bought to see if you won cancer. You will never buy a lotto ticket that doesn't have a chance of winning.
ETA and then there's the non-cancer effects that just increase cardiac problems and stroke risk.