Accidents in which large quantities of dangerous chemicals are released into the environment are almost inevitable in the modern world. Toxic chemicals are produced in such large volumes today that it would be a surprise if such accidents were never to occur. One of the most infamous accidents of this kind occurred at Seveso, Italy, a town near Milan, on July 10, 1976.
The Swiss manufacturing firm of Hoffman-LaRoche operated a plant at Seveso for the production of hexachlorophene, a widely used disinfectant. One of the raw materials used in this process is 2,4,5-trichlorophenol (2,4,5-TCP). At one point in the operation, a vessel containing 2,4,5-TCP exploded, releasing the chemical into the atmosphere . A cloud 100–160 ft (30–50 m) high escaped from the plant and then drifted downwind. It eventually covered an area about 2,300 ft (700 m) wide and 1.2 m (2 km) long.
Although 2,4,5-TCP is a skin irritant, it was not this chemical that caused concern. Instead, it was an impurity in 2,4,5-TCP, a compound called 2,3,7,8-tetrachlorodi-benzo-p-dioxin, that caused alarm. This compound, one of a family known as dioxins, is one the most toxic chemicals known to science. It occurs as a by-product in many manufacturing reactions in which 2,4,5-TCP is involved. Experts estimated that 7–35 lb (3–16 kg) of dioxin were released into the atmosphere as a result of the Seveso explosion.
People living closest to the Hoffman-LaRoche plant were evacuated from their homes and the area was closed off. About 5,000 nearby residents were allowed to stay, but were prohibited from raising crops or farm animals.
Damage to plants and animals in the exposed area was severe. Thousands of farm animals died or had to be destroyed. More than 2.5 tons (225 kg) of contaminated soil were removed before planting could begin again. Short- and long-term effects on human health, however, were relatively modest. In the months following the accident, 176 individuals were found to have chloracne, an inflammation of the skin caused by chlorine-based chemicals. An additional 137 cases of the condition were found in a follow-up survey six months after the accident.
Other health problems were also detected in the human population. About 8% of the exposed population had enlarged livers and a few residents showed signs of minor nerve damage. Some people claimed that exposed women had higher rates of miscarriage and of deformed children, but local authorities were unable to substantiate these claims. No human lives were lost in the accident.
[David E. Newton ]
Harrison, R. M., ed. Pollution: Causes, Effects, and Control. Cambridge, Royal Society of Chemistry, 1990.
Walsh, J. "Seveso: The Questions Persist Where Dioxin Created a Wasteland." Science (September 9, 1977): 1064–1067.
——. "Reporter at Large: Dioxin Pollution of Seveso." New Yorker (September 4, 1978): 34–36+.
Whiteside, T. "Reporter at Large: TCDD Explosion at Icmesa Chemical Plant." New Yorker (July 25, 1977): 41+.
"Seveso, Italy." Environmental Encyclopedia. . Encyclopedia.com. (November 19, 2018). https://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/seveso-italy
"Seveso, Italy." Environmental Encyclopedia. . Retrieved November 19, 2018 from Encyclopedia.com: https://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/seveso-italy
Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:
Modern Language Association
The Chicago Manual of Style
American Psychological Association
- Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
- In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.