Migration of ingested asbestos.

Tissue samples from one test and one control baboon were analyzed by transmission electron microscopy for the presence of chrysotile and crocidolite asbestos. The test animal had been gavaged with cumulative doses of 800 mg each of chrysotile and crocidolite asbestos. An earlier evaluation of these tissues led to the conclusion that ingested asbestos fibers do not penetrate the gastrointestinal tract of the baboon and migrate systemically. However, the present study involved more sensitive methodology, and penetration and migration were clearly demonstrated by the recovery of significant levels of asbestos from test stomach, heart, spleen, pancreas, and blood samples.