Exposure to 2,4-D does not increase cancer risk, but farming may, EPA Administrator Browner was told by the special joint committee of EPA’s Science Advisory Board (SAB) and the Scientific Advisory Panel.
The data are not sufficient to conclude that there is a cause and effect relationship between the exposure to 2,4-D and NHL.
The 26-page committee report said, “When epidemiologic studies alone cannot establish a carcinogenic effect in humans, it is often possible to combine that data with animal studies to establish with high probability that the agent is carcinogenic. In the case of 2,4-D, the chemical has possibly produced astocytomas, but only in rats. Since this cancer site is different from that reported in man, and since the effect has not been seen in studies of 2,4-D in other laboratory animals, these finding do not lend further support to the evidence from the human studies. However, both rats and mice have shown changes ingrowth and thyroxine levels from 2,4-D. Two cohort studies have reported non-significant increases in thyroid, testicular and other endocrine cancers which deserve further study with an increase in the follow-up of these group. At this time, with the expectation of the suggestive associates of Lymphomas and exposure to 2,4-D in free living dogs, the animal data offer no support for the (conflicting) observations in humans, since the carcinogenic effects are very weak, and are limited to a different cancer site and effects which are demonstrable in only one species.”
The committee’s report said: “Therefore, our conclusion at this time is that while there is some evidence that NHL may occur in excess in populations which are likely to be exposed to 2,4-D, the data are not sufficient to conclude that there is a cause and effect relationship between the exposure to 2,4-D and NHL. The data are however, sufficient to require continued examination of the issue through further studies.”
Reprint permission given by AgAir Update, P.O. Box 850, Perry, GA 31069 - an international agricultural aviation publication.
Return to Spreading the Facts