David J. Doolittle

David J. Doolittle was an R. J. Reynolds Tobacco Chemist, circa 1990 -1994. He worked on the project BESSE-Biological Effects of Sidestream Smoke Exposure circa 1993. In 1990, Doolittle wrote:

When considering the | biological plausibility model we must recognize two well-documented observations regarding ETS [environmental tobacco smoke]: 1) Some non-smokers are exposed to ETS as evidenced by subjective impressions (annoyance), and nicotine and cotinine in urine samples. 2) Even though present at very low concentrations, ETS does contain IARC [International Agency for Research on Cancer] human carcinogens, as well as mutagens and cytotoxins.

Thus, we cannot disprove the notion that some non-smokers are exposed to carcinogens, mutagens, and cytotoxins in ETS. Also, even though the level of exposure to these chemicals is extraordinarily small, it is extremely difficult to absolutely prove that these exposures will never adversely affect any individual. This, in effect, forms the basis for the biological plausibility model.