Ozone Selectively Inhibits Growth of Human Cancer Cells Science Vol. 209, 22 Aug 1980, pp. 931-933 Abstract: The growth of human cancer cells from lung, breast, and uterine tumours was selectively inhibited in a dose-dependent manner by ozone at 0.3 to 0.8 part per million of ozone in ambient air during 8 days of culture. Human lung diploid fibroblasts served as noncancerous control cells. The presence of ozone at 0.3 to 0.5 part per million inhibited cancer cell growth 40 and 60 percent, respectively. The non-cancerous lung cells were unaffected at these levels. Exposure to ozone at 0.8 part per million inhibited cancer cell growth more than 90 percent and control cell growth less than 50 percent. Evidently, the mechanisms for defence against ozone damage are impaired in human cancer cells. 24 April 1980; revised 11 June 1980.