From dioxins and EU directives to murder and missing waste, Becky Allen looks at the 1976 disaster's enduring legacy
Today, almost nothing remains of the Industrie Chimiche Meda Società Azionaria (ICMESA) chemical plant in Meda, a small working-class suburb north of Milan. Nothing above ground, that is. A new forest has sprung up; thousands of oak, maple, pine and poplar trees spread across 43 hectares of landscaped parkland.
Buried beneath the Bosco delle Querce lie demolished houses, personal possessions and the remains of 80,000 animals that 37 years ago belonged to the residents of Seveso, the community most affected by the 1976 accident at the ICMESA plant.
As well as human tragedy, Seveso has become synonymous with environmental disaster, lending its name to three European safety directives, bringing dioxins to the world’s attention, and leaving in its wake bombings, shootings and 41 drums of wandering waste.
July 1976
The disaster began 6km north of Seveso in Meda, home to the ICMESA chemical plant. Built in 1971 and owned by Geneva-based Givaudan SA, the facility employed 170 workers and made intermediates for the cosmetic and pharmaceutical industries, including 2,4,5-trichlorophenol, produced by hydrolysis of 1,2,4,5-tetrachlorobenzene.
Early on the morning of Saturday 10 July 1976, the nightshift came off duty, shutting down the manufacturing process as the plant closed for the weekend. The hydrolysis reaction, however, was incomplete: part of the glycol was distilled but the mixture had not yet been diluted with water and hydrochloric acid.
With only maintenance and security teams onsite, pressure mounted in the reaction vessel and just after midday the maintenance foreman, Giuseppe Bruno, heard the sharp metallic ping of a safety disc rupturing, quickly followed by a roaring, whistling noise as a jet of whitish vapour shot into the air from an exhaust pipe.
With no expansion chamber above the bursting disc, ethylene glycol, soda and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or dioxin) – an impurity produced by the overheated reaction – burst through the roof and spread on the north-westerly breeze across Seveso.
During the following days, residents, who found scores of dead rabbits and birds and whose children started suffering from skin rashes, were warned by plant managers not to eat local produce. A week later, on 17 July, Givaudan confirmed dioxin was the cause.
Three evacuation zones were established, between them affecting almost 250,000 people. In zones B and R, where dioxin levels were around 0.9mg/m2, a ban on eating local fruit, vegetables and meat was imposed, and children and pregnant women were evacuated during the day but allowed to return home to sleep.
In zone A, the most heavily contaminated area, where dioxin concentrations reached 580mg/m2 hundreds of residents were evacuated. An air of anxiety pervaded the area, which was sealed off by a 9.5km ring of barbed wire and guarded by armed troops. An employee at Rome’s Institute of Hygiene described the situation as a having a “feeling of imminent disaster”.
Residents had reason to be worried. As well as the evacuations, hundreds of people were treated for dioxin poisoning – including 187 cases of the disfiguring skin condition chloracne – and more than 80,000 animals were culled to stop the poison entering the food chain.
Knowledge gap
As patients were treated, scientists wondered how to cope with the clean-up. Speaking 20 years after the disaster Giovanni Bottari, president of the Fondazione Lombardia per l’Ambiente, the regional environmental research organisation, recalled how little information there was about dioxins.
“At the time that the reactor of the ICMESA factory released several kilograms of 2,3,7,8-TCDD into the atmosphere, very little was known about the effects of this compound on human health and biosystems,” he said.
“We had no reliable measuring techniques or methods to sample dioxin in organic matrices such as plant and animal tissues or human blood. Neither did we have any solid grounds on which to plan effective technologies for remediation of dioxin-contaminated soils and buildings.”
A special emergency office was set up to cope with the disaster. Between July 1976 and May 1978, nearly 13,000 samples – from soil and water to the interiors of school buildings – were analysed and the emergency office worked for eight years overseeing the clean-up, establishing long-term epidemiological studies and monitoring dioxin levels.
Like the monitoring, the clean-up was of epic proportions: 35 families from the most contaminated parts of zone A were rehoused and businesses relocated. Hundreds of homes were cleaned or demolished, and more than 200,000m3 of soil and vegetation removed from gardens. Remaining houses were decontaminated, furniture replaced and thousands of trees replanted.
The debris was buried in two large tunnels beneath what would become the Bosco delle Querce, but it was not until six years after the disaster that clean-up of the plant itself was completed.
Borrowing techniques from the nuclear industry, the plant was sealed, dismantled and the most heavily contaminated waste packed into 41 lead-lined barrels and removed from the site in September 1982 by contractors Mannesmann Italiana.
Missing barrels
For the next eight months, the barrels’ whereabouts were a mystery and, in February 1983, a Swiss TV programme revealed they were “missing”. The journalists traced the waste from Italy to Saint-Quentin in northern France, but there the trail went cold.
In May, the barrels resurfaced in an unused abattoir in the northern French village of Anguilcourt-le-Sart, from where they made their way to a French military base near Sissonne.
On 25 November 1985, more than nine years after the disaster, the Roche Group (Givaudan’s parent company) announced that the waste had finally been incinerated in Switzerland.
Lord Hails told the House of Lords that the barrels had “been making the ‘grand tour’ of Europe, carting about the most deadly poison in the world”.
But the drama had already taken a more violent turn. In May 1977, Dr Giuseppe Ghetti, Seveso and Meda’s medical officer, was shot and wounded during an attack on his office.
The Roche Group’s Milan offices were bombed and in July 1977, on first anniversary of the disaster, the Swiss home of the firm’s chief engineer Rudolf Rupp – who had been sent to Seveso to assist with the clean-up – was also bombed. Then, in February 1980, Paolo Paoletti, ICMESA’s production director, was shot dead by Prima Linea, a tiny Italian terrorist group.
Three years later, in June 1983, ICMESA’s managing director, company chair and three others appeared in court in Monza, charged with negligence, causing contamination and safety failures. All five were found guilty and given lengthy prison terms; however, three appealed successfully against their convictions and the remaining two had their sentences suspended.
Lasting legacy
Close to four decades on, Seveso’s legacy remains considerable. Not only does much of what we now know about dioxin toxicity come from the events of 1976, but the disaster shaped European and UK legislation on major hazards and waste.
Today, some 8,000 industrial sites are covered by the so-called Seveso Directive on the control of major-accident hazards involving dangerous substances and the furore that attended the missing waste was the starting point for international controls on transboundary movement of waste by the OECD.
Former environment commissioner Stavros Dimas said Seveso had “become a shorthand term for major industrial accidents”.
Speaking at an event to mark the disaster’s 30th anniversary in 2006, he explained: “The reason for this particular accident becoming such a symbol is because it exposed the serious flaws in the response to industrial accidents.
“The disaster brought home the need to combine industrial development with the protection of our citizens and the quality of the environment. And it led to the first EU legislation on the accident hazards of industrial activities.”
Since the Seveso Directive was adopted in 1982, it has undergone several modifications, the most comprehensive review taking place in 1996, when Seveso II (96/82/EC) was adopted.
Implemented in the UK via the COMAH (Control of Major Accident Hazards) Regulations 1999, the legislation requires high hazard sites to take all necessary measures to prevent major accidents involving dangerous substances and limit the consequences to people and the environment of any serious incidents that do occur.
The COMAH regulations are being revised in line with Seveso III when it comes into force in 2015.
According to Dimas: “The most remarkable achievement of the Directive has been to instil a culture of safety in industry ... Seveso II introduced new concepts, which have become the pillars of our policy in this area – safety management systems, emergency plans, land-use planning and an effective inspections system. Both inside and outside Europe, Seveso II has become an important benchmark.”
Back in Seveso’s Bosco delle Querce, its small hills are the only sign of the tonnes of soil, rubble and contaminated equipment buried in the two waste-filled tunnels.
Between them they contain almost 300,000m3 of material encased in impermeable membranes and surrounded by water extraction, treatment and outflow systems. The park was landscaped and planted with 5,000 trees and 4,000 shrubs in 1986. And, for many, it remains an important memorial.
“In the basins there lay the memories of the people who were compelled to leave everything on 26 July 1976,” says the local council, the Comune di Seveso.
“Today the forest is a symbolic place: it portrays the struggle against pollution, the toil to recover a seriously compromised environment and the commitment to keep the memory of the disaster alive. It is a token of the ability to react with determination, solidarity and sense of responsibility to environmental damage caused by superficiality and indifference.”
The 'superpoison'
Dubbed the “superpoison” and part of the “dirty dozen” – a group of persistent organic pollutants – dioxins are a group of chemical compounds. The term dioxin usually applies to the family of structurally and chemically related polychlorinated dibenzo-para-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).
Certain dioxin-like polychlorinated biphenyls (PCBs) with similar toxic properties are also included under the term “dioxins”. Some 419 types of dioxin-related compounds have been identified, 30 of which have significant toxicity. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or dioxin is the most toxic.
Although dioxins can be produced by natural processes, such as forest fires and volcanic eruptions, they are mainly unwanted byproducts of industrial processes, from smelting and paper bleaching to pesticide manufacture and incineration.
Dioxins are highly toxic, causing reproductive and developmental problems, immune system damage and cancers. TCDD’s health effects were widely studied after its discovery as a contaminant in batches of the herbicide Agent Orange, which was widely used during the Vietnam War.
Dioxins accumulate in the food chain and more than 90% of human exposure is via food, mainly meat and dairy products, fish and shellfish, and their concentrations in food are widely monitored.
In 1999, high levels of dioxin were found in Belgian poultry and eggs and traced to animal feed contaminated with illegally disposed PCB-based waste industrial oil.
Contaminated feed also led to the recall of tonnes of pork products in Ireland in 2008 after high levels of dioxins were discovered.
And in 2007, the European Commission issued a health warning after high levels of dioxins were detected in guar gum, a food additive. The source was traced to gum from India that was contaminated with pentachlorophenol, a banned pesticide itself contaminated with dioxins.
A few cases of intentional human poisoning have also been reported, most famously the poisoning in 2004 of the president of the Ukraine, Viktor Yushchenko, whose face was scarred by chloracne.
Source: World Health Organisation, 2010.
