eli5: If tobacco is a leaf, why does it have so many substances known to cause cancer?

Question

* Source is the packaging I’ve just read for a pack of tobacco in the UK which says it has 70 cancer causing substances

In: 2

Answer 1

Another “fun” aspect is the polonium-210 content. The high phosphate fertilizer used to grow tobacco is made of a crushed rock. That rock has naturally occurring radium, which decays to polonium. Tobacco is an alpha emitter.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2509609/