Tests of the Additive and Multiplicative Hypotheses of Multiple Exposure

In this chapter, I consider the possible synergistic relationship between tobacco smoking and asbestos exposure. Asbestos refers to a group of naturally occurring flexible fibers that may be separated and woven. There are two major types of asbestos. The first type is amphibole fibers and appears commercially as amosite and crocidolite. The second type is chrysotile. Studies have demonstrated that amphibole fibers are much more dangerous to humans than chrysotile fibers. The fibers are resistant to heat and fire and do not conduct electricity. Asbestos fibers break easily if separated from their bonded finished products and can turn into dust particles that float in the air or stick to clothing.