Benzene, arsenic and cyanide are all poisons. They're all in cigarette smoke too.
"Smoking and Tobacco Control." U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health, National Cancer Institute. Risks Associated with Smoking Cigarettes with Low Machine-Measured Yields of Tar and Nicotine, Oct. 2001.
http://cancercontrol.cancer.gov/brp/tcrb/monographs/13/m13_complete.pdf
"Toxicological Profile For Benzene." U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry. Atlanta, GA., Aug. 2007.
"Toxicological Profile For Arsenic." U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry. Atlanta, GA., Aug. 2007.
"Toxicological Profile For Cyanide." U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry. Atlanta, GA., Aug. 2007.