The oncogenic potential of isoprene as affected by concentration, length of daily exposure, and weeks of exposure over the life-span of the animal, as independent variables, was evaluated. Ten groups were exposed for 8 h/day, 5 days/week as follows (ppm-weeks): 0-80, 10-80, 70-40, 70-80, 140-40,
Isoprene, the monomeric unit of natural rubber and naturally occurring terpenes and steroids, is primarily obtained as a by-product of naphtha cracking for ethylene production. It is emitted from plants and trees, has been detected in tobacco smoke and automobile exhaust, and was identified as a