Biological Effects of
Chrysotile" (1986), can be considered a benchmark among the many important scientific meetings of the last two decades on the effects of asbestos. The first statement of the monograph, by F. D. Pooley and R. Mitha, is as follows: "The only way at present of estimating the dose and effect of asbestos or other dusts in lung-related diseases with any certainty is by assaying the tissue for residual mineral content. " Since then, this statement, which set the tone of the entire symposium, has led many specialists in the field to take a second look toward the causality of asbestos-related mesothelioma and has led some to state that the time has come to reassess the biological effects of chrysotile asbestos.
This question is not a purely academic one, as it also bears important consequences for the courts. For instance, a recent publication of Mealy's Litigation Report [I9871 has reported on the outcome of a litigation involving a shipyard worker, where it was decided that chrysotile asbestos was a cause of his mesothelioma in spite of the fact that the court was aware that the plaintiff had been exposed to substantial amounts of chrysotile and amphiboles. The court's decision apparently was based on the observation that mesothelioma has been observed in a few cases of chrysotile mine and mill worker deaths.
In this commentary, I wish to submit that this decision runs counter to an overwhelming consensus as to the vastly different potentials of the different asbestos fiber types in inducing mesothelioma, which can be judged by the monograph mentioned above and by the following review.
Chug's recently published data [1984a] on fiber lung burden in long-term chrysotile miners and millers are as follows: of six workers with mesothelioma, both chrysotile and tremolite/actinolite/anthophyllite types of amphibole asbestos were found in five of the six. In the other patient, both chrysotile ore components and amosite were found. In the five patients with only the chrysotile ore components,