Considerable progress in understanding how inhaled minerals cause disease in man has been made in the past two decades. This is mostly due to the great amount of human, animal and cell multidisciplinary studies carried out on silica, asbestos and asbestiforms all around the world. Two previous NATO Workshops on "In Vitro Effects of Mineral Dusts on Cells", have been published in the NATO ASI Series (1985 and 1989). The present NATO-INSERM workshop has focused specifically on a group of silicates, named phyllosilicates because of their sheet structure, of which health related effects have been poorly and sporadically investigated. These silicates are presently largely used as filling materials (kaolin, talc, chlorite), insulating materials (vermiculite, micas), adsorbants (sepiolite, attapulgite) and in many other industrial applications. The estimated annual world production is presently 5.5 million tons of talc (1.8 million for Europe) and only in the United Kingdom about 3.5 million tons of kaolin.

The Third International \ orkshop on "The in Vitro Effects of Mineral Dusts" was held on October 1 - 4, 1984 in Schluchsee, Black Forest, Federal Republic of Germany. In six sessions, 93 participants from 14 countries (USA 32, France 17, United Kingdom 12, FRG 11, Canada 9, Belgium 3, Hungary 1, Italy 2, India 1, Nether lands 1, Norway 1, Poland 1, Portugal 1, Turkey 1) treated and discussed the following subjects: - Significance of the physico-chemical properties of inhalable mineral dusts (mine dusts, asbestos, Man-Made Mineral Fibres - MMMF). - Cellular effects of inhalable mineral dusts with special regard to target ce 11 s. - Immune response and immune toxicity. - Carcinogenicity and interrelated genotoxic and non-genotoxic effects. - Effect of cell metabolism in combination with inflammation and fibrogenesis. - Significance and credibility of in vitro test systems. For the pathogenesis of biological effects and diseases caused by inhalable mineral dusts a number of factors may be significant such as: - Type of dust - Dose of dust - Size and shape of dust particles, and especially - Surface properties of dust particles, which inter alia determine the - sorption properties, e.g. for environmental substances."