Warfarin was included in Annex I to Directive 91/414/EEC on 01 October 2006, which is before the entry into force of Regulation (EC) No 396/2005 on 02 September 2008. EFSA is therefore required to provide a reasoned opinion on the review of the existing MRLs for that active substance in compliance with Article 12(2) of afore mentioned regulation. In order to collect the relevant pesticide residues data, EFSA asked Ireland , as the designated rapporteur Member State (RMS), to complete the Pesticide Residues Overview File (PROFile). An evaluation report was submitted on 21 October 2009 confirming that the pesticide use of warfarin is not intended for direct application on any food or feed crop and that no import tolerances for this active substance were notified to the RMS. Submission of a PROFile was therefore not considered relevant. EFSA therefore mainly based its assessment on the conclusions derived in the framework of Directive 91/414/EEC.
On 12 December 2012, EFSA issued a draft reasoned opinion that was circulated to Member State experts for consultation. No comments were received by 15 February 2013 and the following conclusions are derived.
Residues of warfarin are not expected to occur in any plant commodity or in any animal product because the pesticide use of warfarin is not intended for direct application on any food or feed crop, no CXLs are available for this active substance and no uses authorised in third countries were notified to the RMS. A risk assessment is therefore in principle not required. Due to the lack of data regarding mammalian toxicology, plant and livestock metabolism and analytical methods for enforcement of residues, EFSA is however not in a position to recommend any enforcement measure against the potential illegal use of warfarin. It is also not possible to verify whether the default MRL of 0.01 mg/kg, as defined by Regulation (EC) No 396/2005, provides sufficient consumer protection in case of misuse.
As sufficient information was available to demonstrate that warfarin is highly toxic to mammals on repeated ingestion, the compound is in any case not recommended for inclusion in Annex IV to the above regulation. EFSA also recommends that adequate restrictions are being imposed on the authorised products by Member States in order to avoid contamination of the food and feed crops being stored.