GENERAL47950 - Laserfiche WebLink

Home Browse Search

cancer. Ambivalence is not uncommon in epidemiology when dealing with a non carcinogen or a very weak carcinogen. And positive findings are particularly sus- pectwhen they directly conflict with a large toxicology data base. In the case of 2,4-.D, the studies most often quoted are the National Cancer Institutes (NCI) Kansas (1986) and Ne- braska (1990) fans worker studies, both of which received considerable media attention. NCPs much larger and more recent Iowa/Minnesota study, which showed no association between 2,4-D and cancer, has been generally ignored by the media The Kansas study, which did not develop information specific to 2,4- D, but dealt with herbicide use in general, suggested a higher risk of NHL among farmers who applied herbicides twenty-one days a year or more. The Nebraska study showed a statistically non-significant risk of NHL among farmers applying 2,4-D fortwenty-one days a year or more. Both studies relied heavily on infon~nation provided by proxy respondents. That is, in many cases, the person chosen to participate in the study was not available, so next-of kin or neighbors were asked about that person's pesticide use over a period of more than forty yeazs. Subsequent studies have shown that information on pesticide exposure provided by proxies is often in valid. One study shows that proxy respondents tend to overstate exposure to the most widely known pesticides (such as 2,4-D) and understate exposure to the lesser known products. Nevertheless, anti-pesticide advocacy groups base their charges of 2,4-D carcinogenicity almost entirely on these studies. 2,4-D and the [afore Does ttte completion of the 270 re- seazch studies give 2,4-D a "clean bill of health?" The answer to that is both yes and no. Certainly, from the standpoint of science, 2,4-D is is better shape now than it has ever been. Anti-pesticide advocacy groups, however, will continue to attack it, if for no reason other than its high visibility position. Its widespread use make it just too lazge a target to ignore. The thrusts of the attacks will be different, however. Not only aze we now beginning to see attacks on EPA's re- registration program, but attacks on the studies themselves, on dte basis that since they were funded by the industry, as required under the program, they aze inevitably tainted and should not be considered seriously. Attacks on the EPA program itself, coming from advocacy groups with help from mainstream media, present the program as an enormously expensive boondogle, which allows "dangerous" products such as 2,4,-D, which "causes cancer in laboratory animals" (ABC World News Tonight with Peter Jennings, July 24, 1995), to remain on the market. The fact that most of the studies are not performed by industry or Task Force members, but are contracted out to independent laboratories which have EPA's confidence and a proven ability to follow EPA's extraordinary stringent Good Laboratory Practices (GLPs), is appazently of no consequence. It's a bit ironic that the same advocacy groups who initially, strongly supported the EPA re-registration program, now seem to be attacking the results. In Hte case of 2,4-D