I almost hesitate to type this out, because anyone arguing in favor of the relative safety of tobacco tends to look like they're rationalizing something they want to do, or just being a fool.
HOWEVER, pipe smoking, where the smoke is merely drawn into the mouth and blown out again, is probably the least dangerous use of tobacco. In the 1964 Surgeon General's Report on Smoking and Health, which was the death knell of cigarette smoking, pipe smoking barely registered. The increased death rate of "moderate" pipe smokers over non-smokers barely registered, or at worst was a several percent increase. This is why many cigarette smokers tried switching to pipes, which probably increased the statistical dangers of pipe smoking since many kept inhaling the smoke. (which I couldn't do if I wanted to.)
So, at the risk of being an idiot, I'd say that WHILE TOBACCO IS A KNOWN, PROVEN, CARCINOGEN, pipe smoking is probably the safest way to enjoy it. You makes your choices and takes your chances.