What are the risks for exposed workers?

What are the risks for exposed workers?

By the AVICENN team – Last modification January 2024

New properties, new risks?

At the nanometric scale, materials can have enhanced or new properties, some potentially dangerous for exposed workers (higher reactivity, explosiveness, flammability, etc.).

Among them, the potential for emissions and occupational exposure to aerosols during operations involving nanomaterials has been considered one of the main emerging risks in the workplace since at least 2009 by EU-OSHA¹See Workplace Exposure to Nanomaterials, EU-OSHA, European Agency for Safety and Health at Work, 2009.

Risks still not well understood

The impact that exposure to manufactured nanomaterials may have on human health is still largely unknown and fraught with uncertainty.

Knowledge of the specific health effects on workers is even more limited.

Rare and limited toxicological studies

The scarcity and limitations of toxicological studies do not allow for simple and unambiguous answers on the short-term risks of nanomaterials. In particular, until recently, few studies focused on the inhalation of nanomaterials, even though this is the most likely route of occupational exposure and the one of greatest concern for exposed workers²See our fact sheet on the entry points and fate of nanomaterials in the human body. This exposure is now being given more consideration. Nevertheless, the harmful effects observed in numerous toxicological studies are often contested or minimized by industrialists who try to gain time by waiting for the actual results from epidemiological studies.

An exposure that is difficult to measure

Despite the development of more efficient tools (in terms of sensitivity, reproducibility, flexibility) and of improved knowledge³See in particular the work of INRS on nanomaterials, measurements at workstations are not carried out in a systematic and simple manner. This requires high-performance equipment that is often complex to implement, expensive, and combines several techniques, as well as technical skills that are still rare.

Epidemiological studies rarely of good quality

Effects that can take years to appear

Health effects in workers may take many years to appear, after a relatively long period of repeated exposure and latency between the end of exposure and the date of onset of symptoms or discovery of disease⁴“Chronic effects – such as lung and circulatory infections – can take decades to manifest and be diagnosed” – Aída Maria Ponce Del Castillo (ETUI), Nanomaterials in the workplace, What are the issues for workers’ health, May 2013. These conditions are not necessarily specific in nature, as there is nothing to distinguish them from another origin, particularly extra-occupational.

It is difficult to establish a clear cause and effect relationship between occupational exposure to nanoparticles and pathologies

The causal link is even more difficult to determine because workers are often exposed to multiple chemicals:

• in the workplace, with interactions between nanos and “classic” and sometimes dangerous chemical substances that are difficult to identify and control (this is called the “cocktail effect”).
• in everyday life, via non-occupational exposure to nanos and chemicals that the general population is exposed to via food, water, cosmetics, air pollution, etc.

In the meantime, in the absence of indisputable toxicological, epidemiological and biomedical data, raw materials in nanometric form continue to be handled by workers without prior information. However, the French authorities have recognized that “efforts must be pursued to improve knowledge and allow, in particular, to refine the assessment of effects and risks “⁵Response of the French authorities to the public consultation “Towards a strategic nanotechnology action plan (SNAP) 2010-2015”, March 2010. Work on the risks related to occupational exposure to nanos is carried out within specialized platforms on nano risks at INERIS, INRS, and CEA.

Nevertheless, there are worrying signs

Although incomplete, the available data are rather worrying: inhaled nanomaterials can indeed diffuse in the body, be transformed from a physicochemical point of view, and then accumulate in certain organs, in the blood and inside cells⁶See our fact sheet on the entry points and fate of nanoparticles in the human body and cause disturbances or even harmful effects (pulmonary inflammatory reaction; pulmonary fibrosis; risks of lung cancer in case of inhalation of titanium dioxide nanoparticles and carbon nanotubes for example⁷See our bibliography “Nanomaterials and occupational health and safety” and especially:
– ROS/RNS Leakage During Frustrated Phagocytosis of Glass Nanofibers Characterized by Nanosensor and its Implications on Lung Injury, Qi YT et al., Nature Nanotechnology, January 2024
– Barthel et al., Needlelike, short and thin multi-walled carbon nanotubes: comparison of effects on wild type and p53+/− rat lungs, Nanotoxicology, 2023
– Barthel et al., Continuous Long-Term Exposure to Low Concentrations of MWCNTs Induces an Epithelial-Mesenchymal Transition in BEAS-2B Cells, 11(7), Nanomaterials, 2021).

As early as 2014, the French National Agency for Health Safety (ANSES) had advocated the classification of nanomaterials as hazardous substances under the European regulation CLP⁸Evaluation of the risks associated with nanomaterials – Issues and update of knowledge, ANSES, April 2014 (posted online May 15, 2014).

The risk of fire and explosion is also particularly worrying (especially for aluminum, magnesium or lithium nanoparticles as well as for carbon nanotubes)⁹See in particular:
– Nanomaterials in transport and housing: What are the risks related to thermal degradation, Simon Delcour, LNE, wébinar, June 2019
– Army scientists have a blast with aluminum nanoparticles, U.S. Army Research Laboratory, June 7, 2018.

What are the similarities with asbestos?

In animals, effects similar to those of asbestos have been observed: rats in the laboratory have developed mesothelioma following exposure to certain types of carbon nanotubes. The toxicity of carbon nanotubes has been clarified by numerous studies and not all have the same potential for danger. The longer and thinner they are, the more dangerous they are¹⁰See our sheet on the risks of carbon nanotubes. As in the case of asbestos, the consequences of a lack of prevention are worrying because the effects on health are likely to appear several years – or even decades – after exposure to nanomaterials… hence the need to protect workers and to set up a device to monitor their long term health condition.

Various cases of pathologies already reported

Several cases of pathologies observed in workers exposed to nanoparticles have nevertheless already been reported:

Note, at the end of 2017, a legal “first” in Europe on occupational exposure to nanoparticles: a Spanish judge considered that a worker who had undergone a kidney transplant should not be assigned to a position exposed to nanomaterials¹⁵Prevecion integral, Primera sentencia en Europa sobre exposición a nanopartículas, 15 December 2017 (Una juez de Pamplona decide, en una sentencia admirable, que un trasplantado de riñón es especialmente sensible a las nanopartículas). This opinion could have significant implications in the years to come.

What protection is needed?

Too little protection for workers exposed to nanomaterials

Ten years ago, companies in France and abroad were not able to protect the health and safety of their workers from the risks of nanotechnology¹⁶See in particular:
– C.D. Engeman et al, Governance implications of nanomaterials companies’ inconsistent risk perceptions and safety practices, Journal of Nanoparticle Research, 14 (3), 1-12, February 2012
– INRS, Repérage des salariés potentiellement exposés aux nanoparticules, Références en Santé au travail, n°132, December 2012
– Conti J.A. et al. Health and safety practices in the nanomaterials workplace: results from an international survey, Environmental Science & Technology, 42 (9), 3155-3162, 2008. The situation is slowly improving: personal protective equipment (PPE) and collective protective equipment are gradually being introduced, particularly for research and development laboratory staff. These issues of safety of use and health risks are beginning to be taken more into account, but there is still much to be done and efforts must be intensified.

Companies reluctant to participate in risk research efforts

In April 2019, INRS launched a first call to companies using amorphous silicas for research in occupational health: “Occupational exposure to nanostructured amorphous silicas: biomarkers of early effects” (2019-2022). Due to a lack of responses, INRS had to launch a new call two and a half years later, in September 2021… Were more companies recruited? Not really, and the gap between the corporate social responsibility (CSR) claims and the reality can be clearly seen…

Too few practical and directly applicable recommendations

Apart from the publications of INRS, the High Council for Public Health (HCSP) or the European Agency for Safety and Health at Work (EU OSHA),¹⁷see our bibliography “Nano and Health at Work”, there are few operational recommendations available to professionals: to date, no guidelines, recommendations from the Haute Autorité de Santé (HAS) or learned societies have been published.

Occupational health professionals working in companies have many questions: where are the nanos? how to identify hazards? how to evaluate exposures? what medical follow-up should be carried out? etc. Their observation is unanimous: intervening and advising is complicated; there is a global lack of knowledge of the risks related to nanos. These professionals stress that they are isolated in the field, lack information and have few partners but this should not lead to inaction.

Many of these occupational health professionals (occupational physicians, nurses, technicians or prevention advisors) have joined working groups on the identification and prevention of nanomaterial-related risks since 2016, set up as part of regional occupational health plans (PRST).
Tools to guide action have been developed and disseminated in the Burgundy-Franco-Comté, Pays de la Loire, Auvergne-Rhône Alpes and New Aquitaine regions. In the companies of New Aquitaine, a network of “nano referents” has been set up in the occupational health services of the 12 departments of this large region, with 4 priority areas: traceability of exposure, information and training on risks, advice to reduce exposure to the lowest possible level, and medical surveillance and health monitoring

The trade unions, particularly the CFDT, organize awareness / training sessions on nano-risks, in conjunction with INRS and AVICENN.

Efforts must be intensified

The combination of all these elements lead us to recommend the utmost vigilance, in accordance with the precautionary principle. The stakes are high and the aim is to avoid repeating the mistakes of the past: if the carcinogenic effects of asbestos were demonstrated in the 1930s, it was not until the 1990s that the first prohibition laws came into force…