Experiences from the accident of Seveso.

Provisional data on selected sanitary events which took place at Seveso after July 10 1976 are reported. 187 cases of chloracne, mostly in children, were detected, 50 just after the accident, the others within a year. Most polluted area (zone A) provided almost all "early" and most severe cases, but the territorial distribution of chloracne prevalence rates showed some inconsistencies with the soil TCDD pollution map; interpretations for such findings are discussed. Thirty-eight birth defects were detected in 1977 (none in zones A and B), more than in previous years, but still less than expected in a well controlled "normal" population: no clustering around a given type was observed. Spontaneous abortions, evaluated both as abortion rates and as pregnancy loss rates, showed scattered and statistically non-significant variations, inconsistent with the pollution map. No differences in birth and death rates compared to surrounding areas were observed. Data on ad hoc cytogenetic, neurological and immunological surveys are commented. Limitations of the presently available data are discussed and further research lines are anticipated.