The European Food Safety Authority (EFSA) has concluded that it cannot confirm whether the feed additive montmorillonite-illite mixed layer clay mineral (1g557) remains safe for target animal species under current authorisation conditions, in a scientific opinion adopted on 30 June 2026 and published on 6 August 2026. The opinion, requested by the European Commission following an application from FIM Biotech GmbH for renewal of the additive's authorisation for all animal species, also finds that the additive remains safe for consumers and the environment, but should be considered a skin and respiratory sensitiser, with user exposure by any route posing a risk that should be minimised. The Panel could not conclude on eye irritation due to absence of data.
The assessment, carried out by EFSA's Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), follows the applicant's submission of a dossier on 30 October 2025, which was deemed valid by EFSA on 23 January 2026. A public consultation on the non-confidential dossier ran from 16 March to 6 April 2026, receiving no comments, while a targeted consultation of interested Member States took place from 28 January to 28 April 2026. The European Union Reference Laboratory confirmed that previous methods for controlling the additive in feed remain valid. The additive is currently authorised as a technological additive (binder and anticaking agent) for all animal species, with minimum and maximum contents of 10,000 and 20,000 mg/kg complete feed as a binder, and 20,000 mg/kg as an anticaking agent. The applicant did not request any change to these conditions.
The Panel's inability to confirm safety for target species stems from inconsistencies in the data provided. The applicant initially submitted a dataset of six batches whose mineralogical composition did not comply with the specifications set in the authorising regulation, which require at least 75% phyllosilicates, including at least 35% swellable montmorillonite-illite, at least 30% illite/muscovite, and no more than 15% kaolinite, with quartz capped at 20% and asbestos absent. A subsequent dataset showed compliance, but the applicant provided no explanation for the non-compliance of the first batches or the difference between the two datasets. The Panel noted that some variation is expected from mined products due to natural variability, but the lack of explanation prevented a definitive safety conclusion. Particle size analysis of one batch indicated that the presence of small particles, including nanoparticles, cannot be excluded.
The opinion also reiterates existing risk mitigation measures, including warnings against simultaneous oral use with macrolides and, for poultry, with robenidine, as well as contraindications with other coccidiostats at montmorillonite-illite levels above 10,000 mg/kg. Feed business operators are required to establish operational procedures and use personal protective equipment, including breathing protection, where risks cannot be otherwise minimised. The Panel found no need to assess efficacy in the context of renewal, as the additive's efficacy is not re-evaluated under renewal procedures.
The renewal assessment builds on three earlier EFSA opinions on the safety and efficacy of the additive, issued in 2014, 2015, and 2020. The current opinion will inform the European Commission's decision on whether to renew the authorisation, which is set to expire. The outcome could have implications for FIM Biotech GmbH, the sole applicant, as well as for feed business operators and farmers relying on the additive as a binder and anticaking agent. If the Commission follows the Panel's inability to confirm safety, it may impose additional conditions or, in a worst-case scenario, decline renewal, potentially disrupting supply for animal feed producers. Conversely, the confirmed safety for consumers and the environment, along with the absence of efficacy concerns, supports continued use under existing safeguards. The requirement for protective equipment and the potential for nanoparticle exposure may increase compliance costs for users, while the lack of a definitive safety conclusion introduces regulatory uncertainty for the industry.