Little is known about exposure and risks
There is still relatively little information available on whether working with nanomaterials can lead to health risks. This is partly due to the absence of an overview of companies working with nanomaterials. However, we do know that the risk of exposure to nanomaterials at the workplace depends primarily on the chance of nanoparticles being inhaled. This may, for instance, happen when nanomaterials are handled in powder form or in spray applications (e.g. spray paint), or when processing materials that contain nanoparticles.
It is not a trivial matter to measure or characterise the exposure to nanomaterials at the workplace, as it often requires a combination of various measuring devices. In addition, the hazard potential of only a limited number of nanoparticles has been investigated. Risks related to nanoparticles cannot be derived merely from data on the same substance in non-nanoform. A chemical substance in nano-form may come in various shapes and sizes, each with unique properties and specific risks. This hampers the derivation of health-based occupational exposure limits for nanoparticles. Nano-specific health-based exposure limits are available only for a small number of nanomaterials, most of which do not have any legal status. An overview of health-based exposure limits can be found in the WHO document “WHO guidelines on protecting workers from potential risks of manufactured nanomaterials”.
Tools for estimating exposure and potential risks
An employer is legally required to provide employees with a safe workspace. In view of the uncertain health risks of nanomaterials, a first step is to minimise exposure as a precautionary measure. Various tools are available for that purpose. The Occupational Health and Safety Portal (in Dutch) of the Dutch Ministry of Social Affairs and Employment provides general information on formulating an occupational health strategy and preparing a risk inventory and evaluation (RI&E). These also have to be prepared when handling nanomaterials. Specifically for nanomaterials, the Dutch unions VNO-NCW, FNV and CNV, subsidised by the Ministry of Social Affairs and Employment, commissioned the publication of the ‘Guidance for the safe handling of nanomaterials and nanoproducts' (in Dutch). Occupational health officers can also use the measurement strategy (in Dutch), which was developed in 2014 as part of the research programme NanoNextNL.
Various international guidelines have also been published for assessing the risks involved in working with nanomaterials. Examples of these include the aforementioned WHO guideline and the European guidance for working safely with nanomaterials for workers and for employers and occupational health and safety practitioners.
The Ministry of Social Affairs and Employment recently commissioned an evaluation of the tools and guidelines used for assessing the risks associated with nanomaterials at the workplace. This served as a basis for an overview of more than 40 different tools and guidelines.
Provisional Nano Reference Values
In 2010, RIVM formulated Provisional Nano Reference Values (NRVs) (summary in English) for the 23 most commonly used nanomaterials. These values are to be regarded solely as pragmatic guide values; they do not guarantee that lower exposure levels are safe. Nevertheless, the SER Commission on Occupational Conditions recommended that the use of the NRVs be encouraged as an alternative where exposure limits are not yet available for nanomaterials.
In 2016, commissioned by the Ministry of Social Affairs and Employment, KIR-nano initiated an evaluation of the NRVs. This evaluation was performed by TNO and Bureau KLB. The conclusion was that the NRVs need an update. KIR-nano works on updating the NRVs (in Dutch) by setting health-based target values for groups of nanomaterials.
As a collaborative partner, RIVM is involved in Nanocentre. Nanocentre provides information to SMEs on working safely with nanomaterials. An expert panel (‘Deskundigenplatform Arbo’) was established within the field of occupational health and safety. This panel, consisting of scientific experts, shares knowledge, seeks collaboration and provides scientific interpretations; for example in response to motions or questions from the Lower House of Parliament.