Seveso accident

Are toxic materials being processed This was the cause of the Bhopal accident, and the less disastrous Seveso accident. 

A publication summarises all the then available technical evidence related to the Seveso accident, and recommends operational criteria to ensure safety in commercial processes to produce trichlorophenol [4], All the plant scale incidents were characterised [ 1 ] by the subsequent occurrence of chloracne arising from the extremely toxic and dermatitic compound 2,3,7,8-tetrachlorodibenzodioxin (structure IX, p. S-3), formed dining the thermal runaway reaction and dispersed in the ensuing explosion. It is also extremely resistant to normal chemical decontamination procedures, and after the 1968 explosion, further cases occurred after transient contact with plant... 

The Seveso accident in 1976 also involved the glycol-based process, but differed fundamentally from the 1968 incident. While the latter apparently involved a thermal runaway initiated during the hydrolysis reaction by application of excessive heat by the faulty hot oil system [7], the process design adopted by Icmesa at Seveso featured heating the reaction vessel by steam at 12 bar (192°C if saturated) to ensure a minimum 40°C safety margin below the known decomposition temperature of 230°C [5]. At Seveso the exothermic hydrolysis reaction had been completed, but... 

Mocarelli et al. (1986) conducted a 6-year study on clinical laboratory parameters of children exposed to 2,3,7,8-TCDD following the Seveso accident. ALT, aspartate aminotransferase (AST), GGT, alkaline phosphatase, cholesterol, and triglycerides in plasma and delta amino levulinic acid in urine were monitored yearly in exposed and control groups beginning in June, 1977, approximately 1 year after the incident. The children were 6-10 years old at the time of the accident 69, 528, and 874 resided in the A, B, and R zones, respectively. Chloracne was seen in 19, 0.7, and 4.6%, of the children in areas A, B, and R, respectively. Blood samples were drawn from 69, 83, and 221 children in areas A, B, and R,... 

In residents of Seveso, Italy, a significant rise in the incidence of birth defects, as compared to pre-accident levels, was observed the year after the accident (Bisanti et al. 1980). A variety of birth defects were observed, but the incidence for any particular defect was not elevated. The authors suggest that the rise in birth defects may not be related to 2,3,7,8-TCDD exposure. Prior to 1976, birth defects in Italy were usually under reported the authors note that the reported incidences of birth defects after the accident (23 per 1,000 births) were similar to incidences reported in other western countries. Thus, the increased incidence may be reflective of the increased reporting rather than an increased number of birth defects. In a study which assessed the risk of birth defects for the 6-year period after the Seveso accident, no increases were observed for the risk of total defects (RR of 1.2, 90% Cl of 0.88-1.64 for zones A and B and RR of 0.97, 90% 0=0.83-1.13 for zones A, B, and R), major defects RR of 1.02, 90% 0=0.64-1.61 for zones A and B and RR of 0.83, 90% 0=0.67-1.04 for zones A, B and R), and minor defects RR of 1.44 90% 0=0.92-2.24 for zones A and B and RR of 1.14, 90% 0=0.92-1.42 for zones A, B and R) (Mastroiacovo et al. 1988). The small number of observed birth defects limits the statistical power of this study to detect significant increases in a specific defect. 

Children s Susceptibility. A limited number of human studies have examined health effects of CDDs in children. Data from the Seveso accident suggest that children may be more susceptible to the dermal toxicity of 2,3,7,8-TCDD (chloracne), but it is not known if this would be the case for other effects. Follow-up medical surveillance of the Seveso children (including measurement of serum 2,3,7,8-TCDD levels) would provide information on whether childhood exposure would pose a risk when the individual matures and ages. The available human and animal data provide evidence that 2,3,7,8-TCDD can cross the placenta and be transferred to an infant via breast milk. Although information on the developmental toxicity of CDDs in humans is limited, there are extensive animal data that the developing... 

Bertazzi PA, Zocchetti C, Guercilena S, et al. 1997. Dioxin exposure and cancer risk A 15-year mortality study after the "Seveso Accident". Epidemiology 8 646-652. 

Mottura A, Zei G, Nuzzo F, et al. 1981. Evaluation of results of chromosome analyses on lymphocytes of TCDD exposed subjects after the Seveso accident. Mutat Res 85 238-239. 

Under forcing conditions chlorine can be displaced by nucleophiles according to the mechanism described in this chapter also in compounds with fewer or weaker electron accepting substituents than hitherto mentioned. This explains the formation of tetrachlorodibenzodioxin ( dioxin ) from sodium trichlorophenolate in the well-known Seveso accident ... 

The 1977 Seveso accident, which resulted in the contamination of a large area of Northern Italy with dioxin, further increased the societal pressure for safer production, use, and disposal of chemicals, and the activation of coalitions within the European Community. The authority to introduce environmental legislation was also strengthened... 

Pesatori AC, Consonni D, Bachetti S, et al. (2003) Short-and long-term morbidity and mortality in the population exposed to dioxin after the Seveso accident. . Industrial Health 41 127-138. 

The Pesticide Manual describes 5 pyridine carboxylic acid derivatives, 3 benzoic acids, and 10 aryloxyalkanoic acids in current use as herbicides. 2,4,5-T seems to be banned worldwide and is not included in the current issue (Tomlin, 2000) but is described in earlier issues (e.g., Worthing, 1979). It was first registered in 1948 by Amchem Products, Inc., Pennsylvania, and the Dow Chemical Company, and was mainly used to control shrubs and trees, for example, in forests and along railways. Although the content of dioxin was eventually controlled, with a limit of <0.05 mg/kg in the preparation, it was banned soon after the termination of its use in Vietnam. Other products with 2,4,5-trichlorophenol were also banned or restricted after the Seveso accident (see Hay, 1978a, 1978b). 2,4-D is also produced from a chlo-rophenol and may contain dioxins, but of the much less toxic congeners. It... 

Very soon after the Seveso accident people got skin lesions, though no increase in mortality was recorded. Total cancer incidents have not increased, but when looking at different types of cancer, mortality associated with leukemia in men and bone marrow cancer in women showed an increase. An increase in mortality due to heart disease in men has been recorded, but this may be attributed to stress. A further tragic result of the accident was the death of the factory director, who was shot dead while he accompanied his children to school. The so-called Seveso directive, valid in the EU since 1982, states that workers and the public shall know about the hazards from industry, and that security measures in case of accidents should be worked out and implemented. 

The Seveso accident is summarized from the dossiers Seveso 20 years after (FLA, 1998) and from the report Seveso, twenty years after (La Roche, Ltd, 1997) which include several details about the event and... 

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