(a) Overview of experimental design. Mice were exposed from 4 to 7 weeks of age and lung tumor incidence was assessed 40 weeks after the end of exposure. (b) Proportion of mice with lung tumors in THS (black) and control (white) groups. The P-value was obtained using Chi-square test. (c) Representative images of lung tumors from THS exposed mice and their corresponding H&E stains.