Abstract
Examination of extensive laboratory data collected during the past four decades, particularly those unpublished data generated in the 1950s and 1960s, indicates that none of the materials used as casing materials (sugars, licorice, cocoa) and humectants (glycerol, propylene glycol, other glycols) on smoking tobacco products, particularly cigarettes, imparts any significant adverse chemical or biological properties to the mainstream smoke (MSS) from cased and humectant-treated tobacco, a conclusion reached by Doull et al. (1) in their assessment of available information on nearly 600 flavorant, casing material, and humectant ingredients variously used as cigarette tobacco additives in the U.S. Tobacco Industry. Addition of casing materials and humectants to the cigarette tobacco blend produced no significant increase in the cigarette MSS of either the total polycyclic aromatic hydrocarbon (PAH) or the benzo[a]pyrene (B[a]P) content, MSS components that have been of considerable interest for many years. Examination of the transfer of humectants from the humectant-treated tobacco to cigarette MSS indicates that the humectants act as significant diluents to the remaining MSS particulate-phase components generated from the tobacco during the smoking process. This dilution decreases the effects observed in several bioassays, e.g., mutagenicity determined in the Ames Salmonella typhimurium test.