Estimation of the TCDD toxic potential in the light of the Seveso accident.

Two years after the TCDD release in Sevesco from the assessment of the acute and midterm effects on the health of the population exposed to known level of contamination the following facts emerged. Chloracne appeared mainly in a small nuber of children mostly with mild severity and quick recovery. Immunoresponse remained normal and susceptibility to infectious diseases was not increased. Peripheral nervous system was not affected in these children nor were the hepatic functions and the urinary porphyrin excretion. Fetal losses and birth defects remained within the expected rates. Newborn growth and development proceeded normally. Chromosome examinations did not reveal abnormalities in number and patterns. A case of intercurrent death provided for the first time TCDD tissue levels in man 6 months after the exposure.