On the night of September 25-26, the Rouen plant of the American chemical giant Lubrizol suffered a major fire that mobilized more than a hundred firefighters for hours.
The fire affected a storage unit at this Seveso classified site, containing mainly additives, complex mixtures of processed hydrocarbons, sulphur-based and phosphorus compounds, and other products intended either to enhance certain properties of base oils or to provide them with new ones.
A plume of toxic black smoke was released from the fire and was estimated to be over 130 square kilometres in size.
This is not the first incident on this site that in 1974, 1989 and 2013 had been the scene of leaks of mercaptan, the gas used to "perfume" city gas. At the time of the last incident, this pollution had been felt as far as Paris (more than 100 kilometres) and in the south of England (about 200 kilometres). More recently, in 2015, a leak had caused about 2000 litres of mineral oil to be dispersed in the city's sewers.
What are the areas affected by the pollution from the Rouen fire?
More than 200 municipalities in Seine-Maritime, Oise, Aisne, Somme and Nord are subject to decrees that block food products produced in the open air under the responsibility of farmers, until health guarantees are obtained.
This does not mean that there are not more affected municipalities.
The Royal Meteorological Institute issued a statement indicating that the pollution cloud had reached Belgium only a few hours after the fire started and that the fumes had continued further north towards the Netherlands.
If you draw a line between Rouen and the Netherlands, you pass not far from many urban areas such as Amiens, Lens, Lille, Roubaix, Ghent, Antwerp... Obviously everything depends on the winds that disperse the pollution over distances of several hundred kilometres affecting hundreds of thousands of people without taking into account borders or official declarations.
What is the nature of the products stored and dispersed during the fire?
Soot is in a particulate state with a diameter of less than one micrometre, which classifies it as PM 2.5 particles.
Their small dimensions allow them to penetrate into the pulmonary alveoli.
Soot is toxic in itself, but it is also an important vector of contamination because it is surrounded by an organic carbon envelope composed of a complex mixture of unburned hydrocarbons, various more or less volatile organic compounds including Polycyclic Aromatic Hydrocarbons (PAHs), acids, PolychloroBiphenyls (PCBs), alcohols, ketones, sulphur and metals.
What are the health risks in the fallout zones?
On September 27, a decree banned the harvesting and sale of crops and animal products in the Rouen region, in contrast to the statements made by some officials such as the Minister of Ecological Transition, Elisabeth Borne, who said:
Yes, there is a very disturbing smell but no health problem
The authorities recommend that private individuals do not consume contaminated products in their vegetable and allotment gardens. The toxicity of the fallout from the fire is therefore well recognized.
The European Food Safety Authority considers eight PAHs to be carcinogenic when they are present in food (EFSA, 2008).
IARC has reassessed the carcinogenic effects of PAHs, and has classified 15 of them as known, probable or possibly carcinogenic substances (2008), and several cancers potentially related to PAHs are listed in occupational disease tables.
PAHs are not the only toxic compounds concerned, soot microparticles can agglomerate different compounds such as heavy metals, PCBs and aromatic hydrocarbons, all known for their dangerousness.
Food is the main route of exposure to contaminants. Food contamination can occur through the deposition of airborne particles on plants, or accumulation in animal species (meat, fish).
But as with fine particles, exposure can also occur through fine particles in the inhaled air.
Why do a combustion residue test?
Since the fire, the population of Rouen but also of the surrounding municipalities, aware that pollution can be everywhere, is obviously very worried and many demonstrations have taken place to ask for reliable information on the risks of pollution in schools, homes, offices, gardens....
The first information obviously comes from public services, it must be followed, but it is often insufficient. Indeed, the analyses carried out can only be partial given the extent of the pollution.
On the other hand, if the danger of acute contamination shortly after the fire is not only very high but also well understood by all, the danger of chronic contamination after the passage of the polluting cloud is often underestimated.
For André Cicolella, chemist and president of the Réseau environnement santé, the effects of the fire in Rouen could prove to be long-term.
The long-term effect is that chlorinated dioxin-like substances will enter the body and remain there for decades. It will be stored in fat and contaminate all living organisms. And the main issue in this case is the protection of pregnant women, because the fetus can be impacted with extremely important consequences.
To have accurate information about your home or workplace, especially in the presence of sensitive people, children, pregnant women, it is useful to carry out a voluntary test to detect combustion residues.
Only an independent laboratory test can accurately assess the actual level of contamination and act accordingly to preserve the health of the occupants.
The combustion residue detection test determines whether the content of residues recognized as toxic, PAHs (Polycyclic Aromatic Hydrocarbons), VOCs (volatile aromatic organic compounds, benzene, toluene, ethyl benzene, xylenes, naphthalene) formed or transported by the fumes during the combustion of organic materials are present in the dust at levels exceeding the recommended thresholds.
Recommendations can be issued and if necessary a more thorough cleaning of the house will be necessary.