[en] Twenty rats were exposed to dust particles of chromium-cobalt alloy abrasives produced in dental material handling. The exposure was carried out in chambers for periods up to 107 days at consentrations of particulate matter of about 10-50 mg/m³. The content of chromium and cobalt in autopsy specimens of lung, liver, kidney and trachea was measured with nuclear techniques. The alloy particles were found to be markedly accumulated in lung tissue. Increased levels of chromium and cobalt were also observed in the trachea. In addition, a moderate increase of cobalt in liver and kidney was demonstrated. The lungs of six exposed rats were examined microscopically. The main part of the dust particles was observed within macrophages. Only a minor fraction of particles were seen in the bronchial lumen close to the epithelial surface. The majority of dust-filled macrophages were located in groups within the bronchial wall or in the interstitium close to the terminal broncheoli. No fibrosis, dysplasia or tumor formation occurred. No acute adverse effects in the lungs were observed. (author)