During the seventeen hours of the fire in the Lubrizol and Normandy Logistics warehouses, the toxic smoke clouds produced by the fire deposited toxic residues over several hundred kilometres northeast of Rouen.
Smoke and soot from fires are classified as carcinogenic substances known to humans by the World Health Organization (WHO).
In the case of a chemical fire, the toxicity of the burned products is added to that of the fumes and soot.
The authorities and associations have taken numerous samples to assess the risks to the health of the inhabitants. Research into heavy metals, asbestos, combustion residues and dioxins is underway to identify known risks.
Emergency investigations must now be completed to assess medium- and long-term health risks. It will take several months or even years before the findings of the investigations are available to the general public.
It is therefore now up to each person concerned to have their own analyses carried out in order to identify the pollutants carried by the toxic cloud and to take measures to limit their exposure.
To which toxic substances are the populations of Rouen and the municipalities in the north-east of Rouen exposed?
The molecules to be investigated first are fire markers, Polycyclic Aromatic Hydrocarbons (PAHs), the analyses carried out generally concern a series of 16 PAHs:
Benzo[a]pyrene (CAS 50-32-8), Benzo[a]anthracene (CAS 56-55-3), Chrysene (CAS 218-01-9), Benzo[k]fluoranthene (CAS 207-08-9), Benzo[b]fluoranthene (CAS 205-99-2), Naphthalene (CAS 91-20-3), Acenaphthylene (CAS 208-96-8), Acenaphthene (CAS 83-32-9), Anthracene (CAS 120-12-7), Benzo[ghi]perylene (CAS 191-24-2), Indeno[123cd]pyrene (CAS 193-39-5), Dibenzo[ah]anthracene (CAS 53-70-3), Phenanthrene (CAS 85-01-8), Pyrene (CAS 129-00-0), Fluorene (CAS 86-73-7), Fluoranthene (CAS 206-44-0).
Where is the pollution?
The analyses of the samples carried out by INERIS for the Rouen Prefecture attest to the pollution of the environment by PAHs.
PAHs are present on the fine particles we inhale and in the dust that settles on and in buildings.
Dust from the outside is imported into buildings through ventilation and shoe soles and for these reasons household dust has been shown to be indicative of outdoor pollution.
As we spend more than 80% of our time inside buildings, it is inside homes and offices that our exposure is the most important.
What are the specific chemical markers of the Lubrizol fire?
The list of chemicals supplied by Lubrizol shows that the warehouse contained several thousand tonnes of chemicals, mainly mineral oils composed of heavy hydrocarbons and about 100 chemical additives.
These are all chemicals to be looked for in samples taken by residents and authorities and which constitute evidence of pollution related to the fire at the Seveso facility in Lubrizol.
The toxicities of the products contained in the Lubrizol and Normandy Logistics warehouses are poorly documented, but the Seveso classification of the installations indicates with certainty that the products stored presented a risk to humans and the environment.
This complex high-temperature mixture combined with chemicals used to fight industrial fires can react and form new unknown toxic products that are not sought in conventional emergency analyses.
As a result, there is still uncertainty about which products to look for in order to carry out a detailed health risk assessment for exposed populations.
How to identify the specific chemicals of the Rouen fire?
To know the real nature of the pollution, it is therefore first imperative to carry out a specific analysis to identify the unknown products present in the soot.
The chemical signatures of the detected molecules are cross-referenced with a database and thus allow the identification of the chemicals present in the sample.
This recognition is an essential step in assessing the health risks to residents of areas affected by the fallout from the smoke cloud.
Only a specific analysis can identify the characteristic markers of Lubrizol pollution
The analyses selected by YOOTEST measure this pollution in the indoor environment of buildings affected by the fallout of toxic fumes. This research must be carried out in two stages:
As a first step, a "fire pollution test" will be carried out to demonstrate the presence of PAHs. These toxic products should be sought as a priority in order to assess the health risks of occupants (housing and professional premises).
Then, if this test shows the presence of PAHs at unusual levels, then a complementary analysis called "screening" will search for the signature of heavy hydrocarbons considered as specific chemical markers of mineral oils burned during the Lubrizol fire.
Attention, in the context of a legal procedure, samples must be taken by a person sworn in as a bailiff.