Respirable rigid fibres are considered more hazardous than non-rigid fibres. However, there is currently no standardised method to measure fibre rigidity. A new approach uses techniques to identify changes at the molecular level in cells. This approach can distinguish between different types of carbonaceous materials. The researchers could tell the difference between rigid fibres, non-rigid fibres, and non-fibrous carbonaceous materials. For this they looked at which biological pathways were affected. This method will help group different types of fibres into hazard categories based on their rigidity.

Bioaccumulation assessment of nanomaterials cannot be done using the equilibrium partitioning method commonly used for organic chemicals. Therefore, the current guidance on bioaccumulation assessment is not suitable for nanomaterials. To address this issue, the OECD has proposed a tiered approach designed specifically for nanomaterials. This approach is tailored for metallic and metal oxide particles but can likely be extended to other advanced (nano)materials as well.

Integrated approaches to testing and assessment (IATAs) can optimise testing strategies and minimise the use of test animals in chemical risk assessment. Recently, aquatic IATAs have been developed that efficiently integrate the limited information on the fate and effects of nanomaterials. This approach can significantly improve the risk assessment of nanomaterials. However, IATAs are not yet widely accepted or implemented in regulatory risk assessment.

Two recent studies have proposed new methods to detect the presence of nanoparticles in food and cosmetics. The first study suggests a two-step approach to detect the banned food additive E 171. This involves screening for elemental titanium, followed by detecting nano-sized titanium dioxide. The second study used a quick screening tool to identify the presence of seven different nanoparticles in facial cosmetics. However, both methods have only been partially validated, and further improvements are required. There is a lack of reliable data on background titanium concentrations in food. A lack of reference matrices with known amounts of nanoparticles in consumer products is another challenge that needs to be addressed.

The use of Artificial Intelligence (AI) applications is quickly increasing and has the potential to revolutionize chemical risk assessment. For predicting the toxicity of nanomaterials, current models only work for relatively simple nanomaterials. There is a need to anticipate current developments and strategies to prepare for future AI implementation in chemical regulation.

Researchers from the EU Graphene Flagship have highlighted the complexity of assessing the safety of graphene and related materials. Such assessment requires detailed knowledge of safety-related physicochemical properties and the development of harmonised test methods. These lessons must receive ample attention in future innovation programmes on new materials.

By 2023, two European research projects related to the Malta Initiative were completed: Gov4Nano and NanoHarmony. These projects provided scientific support to thirteen OECD projects aimed at developing or modifying OECD Test Guidelines or Guidance Documents. However, more work is needed to finalise the OECD documents. The Malta Initiative has also identified further needs for harmonised test methods for future (advanced) materials and animal-free safety testing. The NanoHarmony White Paper guides on how to continue developing these test methods. However, it is uncertain how to identify and address future needs in the absence of resources for funding.

The safety of fullerenes in cosmetic products is uncertain, according to the EU Scientific Committee on Consumer Safety (SCCS). The information provided by the Notifier on the possible genotoxicity of fullerenes and other concerns was insufficient. The European Commission has recently proposed a new rule requiring the industry to provide additional data in the short term. If the industry fails to do so, fullerenes will be banned for use in cosmetic products, like other nanomaterials.

Two years ago, the EU banned the use of the white food colourant titanium dioxide (E 171), because of concerns regarding genotoxicity. Yet, products with this food additive may still be found on the European market. Several institutes outside the EU do not share EU concerns. Therefore, titanium dioxide remains being used in food products outside the EU. As a result, imported products are a potential source of illegal presence of titanium dioxide in food on the EU market.