Recital 33

The development of certain AI systems and AI models may involve the collection of large amounts of data, including personal data and special categories thereof. Special categories of personal data may residually exist in the training, testing or validation data sets or be retained in the AI system or the AI model, although the special categories of personal data are not necessary for the purpose of the processing. In order not to disproportionately hinder the development and operation of AI and taking into account the capabilities of the controller to identify and remove special categories of personal data, derogating from the prohibition on processing special categories of personal data under Article 9(2) of Regulation (EU) 2016/679 should be allowed. The derogation should only apply where the controller has implemented appropriate technical and organisational measures in an effective manner to avoid the processing of those data, takes the appropriate measures during the entire lifecycle of an AI system or AI model and, once it identifies such data, effectively remove them. If removal would require disproportionate effort, notably where the removal of special categories of data memorised in the AI system or AI model would require re-engineering the AI system or AI model, the controller should effectively protect such data from being used to infer outputs, being disclosed or otherwise made available to third parties. This derogation should not apply where the processing of special categories of personal data is necessary for the purpose of the processing. In this case, the controller should rely on the derogations pursuant to Article 9(2)(a) – (j) of Regulation (EU) 2016/679.