Tobacco smoke is a toxic and carcinogenic mixture of more than 5,000 chemicals. The present article provides a list of 98 hazardous smoke components, based on an extensive literature search for known smoke components and their human health inhalation risks. An electronic database of smoke components containing more than 2,200 entries was generated. Emission levels in mainstream smoke have been found for 542 of the components and a human inhalation risk value for 98 components. As components with potential carcinogenic, cardiovascular and respiratory effects have been included, the three major smoke-related causes of death are all covered by the list. Given that the currently used Hoffmann list of hazardous smoke components is based on data from the 1990s and only includes carcinogens, it is recommended that the current list of 98 hazardous components is used for regulatory purposes instead. To enable risk assessment of components not covered by this list, thresholds of toxicological concern (TTC) have been established from the inhalation risk values found: 0.0018 μg day ？1 for all risks, and 1.2 μg day ？1 for all risks excluding carcinogenicity, the latter being similar to previously reported inhalation TTCs.
Burns, DM; Dybing, E; Gray, N; Hecht, S; Anderson, C; Sanner, T; O’Connor, R; Djordjevic, M; Dresler, C; Hainaut, P; Jarvis, M; Opperhuizen, A; Straif, K. Mandated lowering of toxicants in cigarette smoke: a description of the World Health Organization TobReg proposal. Tob. Control？2008, 17, 132–141.
NCI Expert Committee. The FTC Cigarette Test Method for Determining Tar, Nicotine, and Carbon Monoxide Yields of US Cigarettes; U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health: Bethesda, MD, USA, 1997.
Carthew, P; Clapp, C; Gutsell, S. Exposure based waiving: The application of the toxicological threshold of concern (TTC) to inhalation exposure for aerosol ingredients in consumer products. Food Chem. Toxicol？2009, 47, 1287–1295.
Price, PS; Hollnagel, HM; Zabik, JM. Characterizing the noncancer toxicity of mixtures using concepts from the TTC and quantitative models of uncertainty in mixture toxicity. Risk Anal？2009, 29, 1534–1548.
Jarvis, MJ; Boreham, R; Primatesta, P; Feyerabend, C; Bryant, A. Nicotine yield from machine-smoked cigarettes and nicotine intakes in smokers: Evidence from a representative population survey. J. Natl. Cancer Inst？2001, 93, 134–138.
Dunlop, SM; Romer, D. Relation between newspaper coverage of ‘light’ cigarette litigation and beliefs about ‘lights’ among American adolescents and young adults: the impact on risk perceptions and quitting intentions. Tob. Control？2010, 19, 267–273.