First available results of long-term carcinogenicity bioassay on detergency zeolites (MS 4A and MS 5A).

Long-term experimental carcinogenicity bioassay was carried out on MS 4A and MS 5A zeolites. The materials were tested on Sprague-Dawley rats by intraperitoneal, intrapleural, and subcutaneous injection of 25 mg in 1 ml of H2O. The results of this bioassay (the onset of one peritoneal mesothelioma in a male rat treated by intraperitoneal injection of zeolite MS 4A) calls for further and more sophisticated tests on zeolites used as detergents.