Flame retardants are chemical compounds used to prevent fires or slow their spread. They reduce the flammability of combustible materials, increase the fire escape time and thus improve the safety of people and property.
The term “flame retardants” refers to the action of the compound rather than the compound itself. Indeed, different molecules, characterized by compositions (bromine, phosphorus, etc.), physicochemical properties and varied molecular structures, can act as flame retardants.
Incorporated into kitchen utensils, household appliances, furniture, etc.
Flame retardants can be added (as additives) or incorporated (as reagents) into materials such as wood, plastics, cookware, appliances, computers, electrical cables, construction materials, textiles or even furnishing fabrics.
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Several categories of flame retardants, notably bromine-based (polybrominated diphenyl ethers or PBDEs), are now banned in the European Union. However, they remain persistent in the environment, raising concerns.
Released in air, water, dust, food, etc.
The effects of flame retardants on wildlife are documented. Human beings are also exposed to it.
When a flame retardant is incorporated into a manufactured product, reactive processes produce “strong” chemical bonds (these are covalent bonds) between the flame retardant and the polymer matrix blocking most of the flame retardant in the product.
On the other hand, when the flame retardant is added in the form of an additive, these bonds are not formed, which therefore increases the potential for release of the flame retardant into the environment.
Brominated flame retardants or PBDEs have been measured in indoor and outdoor air, house dust, water, sediment and soil and have contaminated the food chain. As flame retardants are widely used in consumer products, the study of indoor environments is particularly important for this group of compounds.
Exposure to flame retardants occurs primarily through inhalation and ingestion of dust. Another source of exposure is food and water contaminated with flame retardants.
An impregnation of the population confirmed by large-scale studies
Impregnation studies, particularly in France, bear witness to this migration of products towards humans. In 2011, within the Elfe cohort, the perinatal component of the national biomonitoring program made it possible to provide the first indicators of the impregnation of pregnant women with brominated flame retardants.
Since then, the Esteban cross-sectional study (Health Study on the Environment, Biomonitoring, Physical Activity and Nutrition) has made it possible to measure the levels of impregnation by brominated flame retardants in the continental French population, from from a subsample of 742 adults and 243 children. The quantification rates of the measured brominated flame retardants were variable depending on the congeners. The majority of them were little or not quantified.
On the other hand, organophosphate flame retardants, which are now more widely used, were detected, for many of the 15 compounds searched for, in a large part of the hair of 259 mother-child pairs from the Elfe cohort, with 9 being detected in more of 20% of samples, and a few in almost all samples.
A public health concern
Given their ubiquity in the environment, the wide prevalence of exposure, and the toxicological and epidemiological arguments, public health concern seems justified for these compounds. The epidemiological monitoring of cohorts such as the Elfe cohort already mentioned but also of specialized cohorts like Pélagie could make it possible, through current projects, to find out more.
But the epidemiologist, who observes the state of health and its determinants, always arrives “after the battle”, once the populations have been exposed. It is therefore better to prevent by strengthening the safety of products placed on the market, including subtle effects such as those on neurodevelopment.
Moreover, rather than regulating them one by one (at the risk of never ending, one compound replacing another), it could be considered to treat them by classes of compounds, as recently suggested.
Risks to the health of populations difficult to quantify
The potential toxicity of different classes of flame retardants is complicated to establish. The European Food Safety Authority (EFSA) has issued several scientific opinions whose conclusions differ.
For certain categories (polybrominated diphenyl ethers or PBDEs) present in foodstuffs such as meat, meat products, fish, seafood), in their opinion, its panel of experts judges that “current dietary exposure to PBDEs in the European population is likely to pose a health problem. The most significant effects concern the reproductive and nervous systems.”
For others (tetrabromobisphenol A and its derivatives), also found in meat, meat products, fish, seafood but also in milk and dairy products, EFSA experts conclude that Current dietary exposure to this category of retardants “does not pose a health problem”. But they recognize a lack of data on the toxicity of derivatives of this molecule.
The benefits in terms of fire prevention in question
More fundamentally, we can ask ourselves whether the benefits in terms of fire prevention are not outweighed by the risks.
Especially since taking into account socio-economic factors conditioning inequalities regarding the risk of domestic fire would make it possible to design targeted and probably more effective measures, including the fight against tobacco consumption, the improvement of security of the real estate stock as well as targeted information on certain populations.
Should we not debate the use of substances democratically, with scientific insight? In the meantime, everyone can always follow some tips to improve the health quality of their home.
The project “Exposure and neurotoxic effects of FLAME retardants – Enflam” benefited from the support of the National Research Agency (ANR), which funds project-based research in France. The ANR’s mission is to support and promote the development of fundamental and finalized research in all disciplines, and to strengthen the dialogue between science and society. To find out more, consult the ANR website.
