Did History Actually Teach Us Anything? - Episode 22 The Seveso Disaster

Laura: Welcome to "Did History Actually Teach Us Anything?" 
The podcast where we unravel the most well-known tales of calamity, mishap, and unforeseen consequences that have shaped the course of history, and consider whether we've actually learned anything from them all these years later.. 
In this podcast, we examine the historical events that you may think you know about already and the causes that led to them, be they icebergs or bakers ovens. 
We will consider whether these tragedies could have been avoided, and some of the surprising things we do differently now as a result. 
But this podcast isn't just about dates and events. It's about learning from the past, drawing insights from hindsight, and gaining a deeper appreciation for the complexities of what really happened in these events we think we know so well. 
So get ready to encounter remarkable individuals, pivotal moments and fascinating insights, that will make you appreciate health and safety and environmental management as far more than just red tape.
On the 10th of July 1976, a quiet town in northern Italy became the site of one of Europe's most infamous industrial accidents. At a small chemical plant near Seveso, a safety system failure released a dense, toxic cloud containing dioxin, a highly dangerous environmental pollutant, into the surrounding area. The leak didn't cause any immediate deaths, but within days, animals began dying, children developed painful skin conditions, and thousands of residents were evacuated from the neighboring areas. Entire communities were uprooted, farmland was contaminated, and the long-term health risks left a legacy of fear and mistrust.
In this episode, we'll explore how a single chemical accident in Seveso became a turning point for industrial safety and public health worldwide. Joining us is one of our health and safety experts, John, who will begin by giving us a brief explanation of the circumstances that led to the Seveso Disaster.

John: The Seveso Disaster occurred in Meda, Italy, which is around 28 km north of Milan, as a result of catastrophic failures at a chemical plant owned by Industrie Chimiche Meda Società Anonima, known as ICMESA, a subsidiary of the large pharmaceutical company, Hoffman-La Roche. The plant made 2,4,5-Trichlorophenol, a substance used to manufacture chemical and pharmaceutical products.
The release of a cloud of toxic dioxin, known as TCDD (which is 2,3,7,8-Tetrachlorodibenzodioxin), into the atmosphere had significant health and environmental impacts on the surrounding area as it was exposed to the dioxin. The cloud severely affected the town of Seveso, around 16 km north of Milan, which at the time of the incident had a population of around 17,000 people. 
The incident led to evacuations, long-term health issues and environmental damage, and prompted a worldwide reevaluation of industrial safety to prevent similar large disasters.

Laura: So what actually happened at the plant that day to cause such destruction?

John: On a quiet Sunday afternoon on the 10th of July 1976, a significant event occurred that was to change the lives of those involved forever. 
The toxic cloud occurred as a result of the chemical manufacturer being stopped before it was finished (the removal of ethylene glycol by distillation was not completed), as the plant had to by law be shut down over the weekend. This led to an increasing steam inside the reactor's shell, from a runaway reaction that heated its contents to a dangerous temperature and pressure.
The condensation from the steam inside the reactor's shell led to an exothermic reaction, causing a cloud of toxic material consisting of sodium hydroxide, ethylene glycol, sodium trichlorophenate and around 15-30 kg of TCDD to be released into the air. The toxic cloud floated over to the Seveso area, ready to cause chaos.

Laura: How was the area of Seveso affected by the release of the toxic cloud into the atmosphere?

John: The initial cloud lasted only for about 20-30 minutes, in which time it released fine droplets that settled onto the ground, contaminating an area of about 18 km². Although its initial release was short, effects of the contamination lasted much longer due to the persistent nature of the chemicals.
Around 37,000 people were exposed to high levels of the dioxin. Those that were exposed suffered from symptoms such as sickness, headaches, skin lesions, and eye and skin irritations.
The area impacted by the cloud was split up into three zones: Zone A (being the most contaminated), Zone B (intermediate), and Zone C (minor concentrations).
Zone A, as you would expect, suffered from numerous severe impacts. Many people developed chloracne - a type of acne caused by chemical poisoning. 26 pregnant women exposed to the toxic cloud chose abortion due to fear, as the chemical was known to cause birth defects.
There was also a significant level of suffering from the area's animals. In Zone A, it is estimated that 25% of all animals died immediately following exposure, particularly chickens and rabbits. By 1978, around 80,000 animals had been culled so that the dioxin would not build up in the food chain, as dioxin accumulate in fatty tissues.
The company confirmed that dioxin was the cause one week after the disaster, on the 17th of July. In Zone A, hundreds of people were evacuated and the area was sealed off with a 9.5 km barbed wire fence guarded by armed soldiers.
The cleanup of the area affected was huge and only ended in 1985, 9 years after the disaster occurred. 35 families were rehoused and many businesses relocated, with businesses in the most severely contaminated area being demolished. Many hundreds of homes were either thoroughly cleaned or also destroyed, and 200,000 m3 of soil and vegetation were taken away from gardens. The waste collected was buried in two large tunnels beneath Zone A, which is now known as the Bosco delle Querce (or Oaks' Wood), 43 hectares of landscape parkland.
Interestingly, waste in 41 barrels from the cleanup operation, such as personal protective clothing and chemical residues, went missing for 8 months until they were eventually found in Northern France in 1983 by a Swiss television channel. From there, they were eventually incinerated in Switzerland in November of that year.

Laura: So what was the chain of events that led to this disaster - were there problems at the plant that caused the release of the chemicals?

John: The Seveso Disaster was primarily caused by a series of errors related to health and safety failings by ICMESA.
Plant operating procedures were poor or not followed correctly. For example, the distillation procedures were completed in reverse and, as I mentioned earlier, the process was stopped before it had been completed.
A safety mechanism, known as a bursting disc, that ruptured to release excess pressure was set to 3.5 Bar, meaning that the release, known as venting, occurred at a higher and more hazardous temperature which caused the emission to be more buoyant and spread further. The control systems at the site, such as sensors and alarms, were inadequate and relied on manual operation, and there were no automatic control systems at the time.
There was also no device that collected or eradicated the emission following venting, allowing it to escape from the building, even though this was recommended by the burst in disc's manufacturer.
Furthermore, there was a failure to communicate the potential risk to the surrounding community, exacerbating the consequences of the incident. Deficiencies in the emergency response and the evacuation plans further amplified the impacts of the disaster, resulting in delays in implementing protective measures to minimize harm to the local population and environment.

Laura: Were there any prevention measures that the plant could have implemented in the first place to stop this disaster from happening? 

John: The Seveso Disaster could have potentially been avoided or its impact significantly reduced to the implementation of comprehensive measures at the plant. 
By introducing more stringent safety protocols and procedures, conducting thorough and regular risk assessments, enhancing monitoring of hazardous substances, ensuring the installation of state-of-the-art containment systems for toxic chemicals, and establishing an effective systems to communicate the risk to the surrounding community, the likelihood of such a catastrophic event occurring could have been greatly reduced. 
Furthermore, with the development and implementation of robust emergency response and evacuation plans that covered all foreseeable situations, including worst case scenarios, the consequences of the disaster could have been better managed, potentially preventing or at least mitigating the devastating impact on the local population and environment.

Laura: So John, did the Seveso Disaster lead to a revision of any health and safety protocols, and did the disaster have any effect on legislation for hazardous industries?

John: The Seveso Disaster prompted a reevaluation of health and safety protocols and regulations, leading to significant changes in industries and regulatory bodies to prevent similar incidents in the future. It emphasized the critical importance of rigorous risk assessments, robust safety protocols, and effective communication of potential hazards to surrounding communities.
It also highlighted the necessity for open and transparent communications with local communities about potential risks associated with industrial facilities. These changes have ultimately contributed to an improved and safer environment for both workers and the surrounding population.
The legacy of the Seveso Disaster was significant, shaping legislation that covered many hazardous industries in Europe. It led to the development of the EU directive on major accident hazards of certain industrial activities in 1982, known as the Seveso Directive (COMAH in the UK). The third and current version of the directive was introduced in 2012. The directive sets significant requirements for organisations that possess dangerous substances, such as preventative measures, mandatory notifications, detailed risk assessment, emergency planning and land use planning around sites. It applies to around 12,000 sites around the EU.
In essence, the Seveso Disaster spurred a fundamental shift in the approach to industrial safety, resulting in more comprehensive and proactive measures to prevent and mitigate the impacts of potential chemical accidents. 

Laura: Thanks for joining us on this episode of "Did History Actually Teach Us Anything?". 
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