Several researchers had responded in these letters to the editor to an article by Fingerhut et al. dealing with the risk of cancer in humans following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (1746016) (TCDD). G. L. Carlo, and K. G. Sung suggest that a earlier study addressed high levels of occupational exposures to dioxin and found no conclusive evidence of cancer risk elevation at these levels. They suggest that dioxin may not be as dangerous a substance as once feared and that exposure to low background levels may not be dangerous at all. R. W. Morgan considers the earlier study to be limited partly by the small size of the cohort. L. Hardell, M. Eriksson, O. Axelson, and M. Fredriksson support the reference study with data of their own and strongly suggest that these findings provide the needed data to conclude that TCDD is a human carcinogen, at least in regard to soft tissue sarcoma. L. R. Goldman, D. Hayward, D. M. Siegel, and R. D. Stephens suggest that the numbers used in the Fingerhut study support the numbers used by the EPA to regulate dioxin exposure. However, they do not support a conclusion that dioxins are less carcinogenic to humans than to animals. In response to these various criticisms, Fingerhut et al. reiterate that the high exposure group had a 46% excess of all cancers combined, that TCDD has produced cancers at a number of sites in animal studies, and that their study provided more than the usual estimate of exposure as they reviewed the chemical processes used, because substantial information was available in the work history records, and because of the very long half life of TCDD biological measurements that could be made long after exposure. J. C. Bailar III supported the view that the evidence indicates a real risk.