What are the poisons in cigarettes?
The same, or equivalent, "poisons"are present in tobacco as in any other plant.
All plants may absorb naturally produced chemicals, such as arsenic and polonium-210, from the environment. Similarly, all plants may absorb "poisons" from man-made pollution or the fertillisers, etc. used to grow them. At the same time, all plants get contaminated with the "poisons" used in their processing. All plants also naturally produce "poisons" to deter predators, to encourage reproduction, etc.
Everything is "poisonous" in the appropriate dose, even water and oxygen.
... Nothing is really safe about cigarettes, pretty much every chemical is toxic to our bodies. Not only do they wreck our lungs but they also damage our cells (brain cells) and attack the respiratory system making it difficult to breathe because the cillia can no longer travel oxygen through our bodies. There are at least 4,000 chemicals in cigarettes