Fifty years after the Seveso disaster released a cloud of TCDD over northern Italy, the incident remains a defining moment in the history of chemical safety – and a stark reminder of the long-term risks posed by persistent organic pollutants.

In 2026, the International Dioxin Conference returns to Italy, bringing experts to Riva del Garda to examine the legacy of Seveso alongside today’s evolving challenges in dioxin, POP, PFAS, and brominated flame retardant (BFR) analysis. The meeting will also, for the first time, be held jointly with the BFR Conference, reflecting the growing overlap between communities working on persistent pollutants and their environmental and health impacts.

Ahead of the conference, we spoke with Werner Tirler, Director of Eco Research and Chair of the Dioxin Conference, about the history of the dioxin issue, why monitoring remains essential, the analytical and financial pressures shaping the field, and how better measurement can help prevent persistent pollutants from becoming tomorrow’s environmental legacy.

Can you briefly explain the history of the dioxin issue, including Seveso? 

Dioxin has become an umbrella term for a group of substances that are toxic and characterized by chlorine substitution at the 2,3,7,8 positions. This classification applies not only to dioxins but also to furans and polychlorinated biphenyls (PCBs) – the so-called “dioxinlike” PCBs. 

Dioxins have never been intentionally manufactured for commercial purposes – there are no commercial applications for these compounds. But they can be formed as by-products during certain chemical or thermal processes.

This was the case in the 1976 chemical accident in Seveso (Italy), where, due to overheating during the production of precursor substances for pesticides, a relatively large quantity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was released. In the days that followed, an increased number of dead animals (hares, birds, chickens) were found in the vicinity of the plant. Shortly thereafter, 200 to 300 individuals developed chloracne caused by dioxin exposure. In the years following the incident, a shift in the birth sex ratio was observed – around 100/80 (female/male), compared to the typical ratio of approximately 100/106. The long-term effects are still under investigation.

The Seveso incident profoundly shocked the public and significantly altered perceptions of the chemical industry. This shift was also reflected in subsequent changes to legislation. The Seveso-Directives I, II and III, (82/501/EC – 96/82/EC and 2012/18/CE)  are European Union directives aimed at controlling major chemical accident hazards. They are implemented in the European National Legislations and are enforced by national chemical safety authorities.

This year marks the 50th anniversary of the event, which is one of the reasons why this year’s dioxin conference is being held in Italy, with a particular focus on the impacts of chemical accidents.

Why is dioxin still important to measure?

Once released into the environment, dioxins can persist for decades due to their extremely low degradability. They are highly persistent and toxic to the environment, as well as to humans and animals. Like chlorinated pesticides (e.g., DDT), dioxins belong to the group of persistent organic pollutants (POPs). In recent years, we have to face a new group of POPs causing concerns: Per- and Polyfluoroalkyl substances (PFAS). It is essential to prevent the release of these substances, because once they enter the environment, they remain there for very long periods and are extremely difficult to remove. 

Critical industrial facilities, such as waste incineration plants, must be carefully monitored because there is an inherent process-related risk of dioxin formation and release. Dioxins can also be emitted from other thermo/chemical industrial plants; however, basically, dioxins (and POPs in general) represent a technical problem for which technical solutions exist. Modern, well-controlled waste incineration plants no longer pose a significant risk. However, as emphasized, strict operational control is essential.

Therefore, detailed analysis by well-trained laboratory experts – capable of accurate characterization and quantification of potential persistent organic pollutants (POPs) – is very important.

What are the main analytical challenges in dioxin and POP analysis?

Persistent organic pollutants (POPs) can pose significant risks to human health and the environment even at very low concentrations. Therefore, high-performance analytical instrumentation is required, along with qualified personnel capable of operating these systems correctly. Mass spectrometers in combination with liquid or gas chromatography (LC-MS or GC-MS) are typically the methods of choice for detecting persistent organic compounds in environmental samples. Ongoing technological advances continue to produce new instrument variants featuring targeted ionization techniques (e.g., APPI, MALDI), enhanced mass resolution (e.g., TOF-MS, Orbitrap-MS), and improved chromatographic separation (e.g., UHPLC, ion chromatography). These developments significantly increase analytical performance and, in many cases, enable the detection of previously unidentifiable compounds. Artificial intelligence is also expected to play an increasingly important role in improving detection reliability and data interpretation.

An important aspect is nowadays the need to make analytical methodologies more environmentally sustainable. The guiding principle is reduction across all inputs: fewer hazardous chemicals, less solvent consumption, reduced use of consumables, and lower energy demand – ultimately, less is more.

What are the key financial pressures in POP monitoring and analysis?

Working with high-performance analytical instrumentation makes it difficult to keep costs low, as the capital investment alone is substantial. To optimize costs, there will likely be a continued consolidation toward fewer but larger analytical laboratories. The increasing pressure to operate in a more environmentally sustainable manner can, in some cases, lead to cost savings due to reduced material consumption. However, this is often offset by the need to invest in new and more expensive technologies, which can negate the economic benefits. Achieving the right balance between cost efficiency and sustainability is important. 

Once persistent pollutants are released into the environment – and particularly if they become detectable within the food chain – they can generate significant costs in the healthcare sector. A critical challenge is that contamination by POPs does not always produce immediate toxic effects that would trigger rapid countermeasures. Instead, such substances can cause chronic, long-term effects, which may ultimately be far more severe. To protect against these risks, comprehensive monitoring networks must be established by authorities, funded by the state – and continuously maintained and operated. While this entails ongoing costs, they are modest compared to the potential burden on healthcare systems if no action were taken.

Why does dioxin require urgent attention today?

Dioxins, as well as other persistent organic pollutants, can exert their harmful effects even years later if humans are exposed to them. The guiding principle – one that should be repeated like a mantra – is: prevent these substances from entering the environment. This places responsibility on regulators, whose role is to protect public health and who can do so through appropriate legislation. Industry, in turn, should design production processes in such a way that the generation of hazardous waste is minimized, thereby reducing the need for disposal. In a fully developed circular economy, waste would not arise at all, as all materials would be reused or recycled. However, responsibility does not lie solely with industry; consumers themselves often choose non-recyclable products, typically due to convenience or cost considerations. These products place a burden on the environment and generate downstream costs that are ultimately borne by society as a whole.

If we aim for true cost transparency, the risks associated with chemical substances must be properly quantified. This, in turn, requires high-performance analytical instrumentation as well as well-trained laboratory chemists.

What will be the focus of the conference?

Just four years after the catastrophic chemical accident in Seveso, the scientific community came together for the inaugural International Dioxin Conference in 1980 to analyze the impacts on an objective basis, with the aim of preventing such incidents in the future. It was through this scientific work that the true extent of environmental contamination by dioxins and dioxin-like substances (e.g., dioxin-like PCBs) was identified and systematically investigated. 

To address the issue as comprehensively as possible, the conference adopts a multidisciplinary approach. Key focus areas include advanced analytical detection methods; emissions; environmental transport and fate; degradation; toxicology; regulatory frameworks; POPs in developing countries; and global environmental contamination. High-performance analytical methods are in strong demand, as new pollutants are continually being identified in the environment and must be quantified as accurately as possible alongside already known substances.

Emissions, transport, and environmental fate ultimately determine where and to what extent POP-related contamination occurs. Detailed toxicological assessment of these substances is essential for establishing effective regulatory measures to protect both human health and the environment.

However, in many developing countries, cost constraints still lead to the use of production technologies that may result in emissions of hazardous substances. Due to the persistence of these pollutants, they can remain in the environment and reappear across diverse regions worldwide even years after their initial release.

Who should attend the conference?

The conference provides a platform for all stakeholders working in the field of environmental contaminants to obtain first-hand information through presentations as well as through direct personal exchange. The Dioxin Conference in Riva del Garda offers an excellent opportunity to engage with scientists from a wide range of disciplines.

Why bring the Dioxin and BFR conferences together?

At Dioxin 2026 in Riva del Garda, an attempt will be made for the first time to jointly organize the Dioxin Conference and the BFR (Brominated Flame Retardants) Conference. Both conferences address researchers working on persistent pollutants with potentially adverse environmental impacts, and both communities employ similar analytical techniques for substance detection.

As a result, there are many areas of overlap, which is why this joint format is being explored this year. However, the core focus of the two conferences remains distinct, and it is not yet clear whether this approach will be continued in the future.

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