Module 3: Toxicology - Section 19: Dioxin
TOX 19.2: Dioxin Toxicity - Case Histories

CASE HISTORIES OF EXPOSURE:

Monsanto

In Nitro, West Virginia, 1949, over 200 workers were exposed. 122 developed chloracne within few weeks. The othershad immediate but transient effects such as headache, dizziness, nausea, weakness.

The 1980 epidemiological study of the 122 chloracne victims (31 years later). Fewer died of cancer than expected in control. Only 32 died from all causes. 46 were expected to die.

Summary - "no excess in total mortality or in deaths from malignant neoplasms or disease of the circulatory system" . The dose unknown, but sufficient to cause chloracne and other immediate symptoms.

Dow

In 1964, 61 employees were exposed to dioxin levels potentially reaching 10,000 ppm (10 µg/kg). 49 developed chloracne. However as of 1980, no excess total deaths were recorded.

Seveso, Italy

In 1976 an explosion occurred while making trichlorophenol, which emitted about 2 kg of dioxin. 37,000 people were potentially exposed (several hundred had symptoms of acute poisoning ( nausea, nervous symptoms, chloracne) - effects from other chemicals not known). There were no deaths.

In Seveso, an extensive surveillance system was put into effect to record long-term effects, involving medical and laboratory tests. Pregnant women were monitored in order to record miscarriages and birth defects, and a cancer registry was created.

Results for all three cases to date:
Does Dioxin Cause Cancer in Humans?
Dioxin/Birth Defects:
Summary:

Epidemiological evidence to date does not implicate dioxin as a cause of birth defects, miscarriages or reproduction in humans. Community exposures (Love Canal, Times Beach, Newark) are substantially lower than in various industrial accidents.



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Postgraduate Diploma in Occupational Health (DOH) - Modules 3: Occupational Medicine & Toxicology (Basic) by Profs Mohamed Jeebhay and Rodney Ehrlich, Health Sciences UCT is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 South Africa License. Major contributors: Mohamed Jeebhay, Rodney Ehrlich, Jonny Myers, Leslie London, Sophie Kisting, Rajen Naidoo, Saloshni Naidoo. Source available from here. For any updates to the material, or more permissions beyond the scope of this license, please email healthoer@uct.ac.za or visit www.healthedu.uct.ac.za. Last updated Jan 2007.
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