Activated charcoal is not carcinogenic, and commonly used in air and water filters.

Charcoal tablets (which is 98% charcoal and some binding agent) is also a common remedy for (traveler's) diarrhea, and perfectly safe for consumption. You can get it in any pharmacy over the counter.

Kent cigarettes had a "Micronite" filter which was made of paper and asbestos.

Charcoal is fine. You can savely eat it and smoking is is probably healthier that tobacco.

Living in Canada, I couldn't wait for the day to try Tareyton cigs, just for the fight.

Could be worse. Kent cigs used asbestos filters.

https://www.motherjones.com/environment/2013/10/lorillard-kent-micronite-filters-asbestos-lawsuit/