Biological tests ty the Centre d'Etudes et Recherches des Chartonnages de France in Verneuil (Cerchar) (6244-00/3/053) and ty the Institut für Hygiene und Arteitsmedizin, Klinikum der Universität Essen in Essen (6244-00/1/011) and the complimentary physical tests ty the Bergtau-Forsohung GmtH (BF) (6253-42/I/OO8) using 'pure' quartz samples from different sources and therefore of different origins, which moreover were comminuted ty different processes and exposed to various temperatures showed that the pathogenicity of quartz varies
Ricerche biologiche del Centre d'Etudes et Recherches des Charbonna ges de France, di Verneuil (Cercher ) (6244-00/3/053) e dell'Institut für Hygiene und Arbeitsmedizin dell'Istituto Clinico dell'Università di Essen (6244-00/l/Ol1), nonché le ricerche complementari della BF