In the January 31, 2003 IRED, EPA concluded that, considering the animal data and the human epidemiological data, atrazine is not likely to be carcinogenic in humans. That conclusion allowed EPA to find that there is a reasonable certainty of no harm from exposure to atrazine so far as cancer risk is concerned. Results in the St. Gabriel study and other recent epidemiological studies regarding atrazines potential link to cancer do not alter that conclusion. Further, any weight attributable to these data is weakened by the data in animals that fail to reveal any mechanism of action for atrazine consistent with the cancers observed in the studies. Accordingly, EPA concludes that atrazine is not likely to be a human carcinogen.