Carcinogenicity studies on vinylidene chloride.

Results of a study on Wistar rats regarding a possible carcinogenic effect of vinylidene chloride (VDC) were presented previously by one of the authors. Due to the unclear character of these results, a second inhalation study was initiated with Sprague-Dawley rats. Groups of 60 animals were exposed to 100 and 75 ppm VDC, along with one control group. A final report on the pathological results must await completion of the microscopic examination of the tissues and organs from all the animals. Nevertheless, it seems clear that there is no grossly observable interrelation between tumor production and VDC inhalation.