Regular cigar smoking is known to carry serious health risks, including increased risk of developing various types and subtypes of cancers, respiratory diseases, cardiovascular diseases, cerebrovascular diseases, periodontal diseases and teeth loss, and malignant diseases.Tobacco smoke is a complex mixture of over 7,000 toxic chemicals, 98 of which are associated with an increased risk of cardiovascular disease and 69 of which are known to be carcinogenic. The most important chemicals causing cancer are those that produce DNA damage, since such damage appears to be the primary underlying cause of cancer. Cunningham et al. combined the microgram weight of the compound in the smoke of one cigarette with the known genotoxic effect per microgram to identify the most carcinogenic compounds in cigarette smoke: acrolein, formaldehyde, acrylonitrile, 1,3-butadiene, acetaldehyde, ethylene oxide, and isoprene. In addition to the aforementioned toxic chemicals, flavored tobacco contains flavorings which upon heating release toxic chemicals and carcinogens such as carbon monoxide (CO), polycyclic aromatic hydrocarbons (PAHs), furans, phenols, aldehydes (such as acrolein), and acids, in addition to nitrogenous carcinogens, alcohols, and heavy metals, all of which are dangerous to human health. A comparison of 13 common hookah flavors found that melon flavors are the most dangerous, with their smoke containing four classes of hazards in high concentrations.The World Health Organization estimates that tobacco caused 5.4 million deaths in 2004 and 100 million deaths over the course of the 20th century.
Many of its chemical properties are similar to those of arsenic and antimony, although they are less toxic than derivatives of those lighter elements. Oxides and sulfides
At elevated temperatures, the vapors of the metal combine rapidly with oxygen, forming the yellow trioxide, Bi2O3. When molten, at temperatures above 710 °C, this oxide corrodes any metal oxide and even platinum. On reaction with a base, it forms two series of oxyanions: BiO−2, which is polymeric and forms linear chains, and BiO3−3. The anion in Li3BiO3 is a cubic octameric anion, Bi8O24−24, whereas the anion in Na3BiO3 is tetrameric.The dark red bismuth(V) oxide, Bi2O5, is unstable, liberating O2 gas upon heating. The compound NaBiO3 is a strong oxidising agent.Bismuth sulfide, Bi2S3, occurs naturally in bismuth ores. It is also produced by the combination of molten bismuth and sulfur. Bismuth oxychloride (BiOCl, see figure at right) and bismuth oxynitrate (BiONO3) stoichiometrically appear as simple anionic salts of the bismuthyl(III) cation (BiO+) which commonly occurs in aqueous bismuth compounds. However, in the case of BiOCl, the salt crystal forms in a structure of alternating plates of Bi, O, and Cl atoms, with each oxygen coordinating with four bismuth atoms in the adjacent plane. This mineral compound is used as a pigment and cosmetic (see below). Bismuthine and bismuthides
Unlike the lighter pnictogens nitrogen, phosphorus, and arsenic, but similar to antimony, bismuth does not form a stable hydride. Bismuth hydride, bismuthine (BiH3), is an endothermic compound that spontaneously decomposes at room temperature. It is stable only below −60 °C.