4. Paragraph 3 of this Article does not preclude a public sector body, the Commission, the European Central Bank or a Union body to exchange data obtained pursuant to this Chapter with another public sector body or the Commission, the European Central Bank or a Union body in view of completing the tasks referred to in Article 15, as specified in the request in accordance with paragraph 1, point (f), of this Article or to make the data available to a third party where it has delegated, by means of a publicly available agreement, technical inspections or other functions to that third party. The obligations on public sector bodies pursuant to Article 19, in particular safeguards to preserve the confidentiality of trade secrets, shall apply also to such third parties. Where a public sector body, the Commission, the European Central Bank or a Union body transmits or makes data available under this paragraph, it shall notify the data holder from whom the data was received without undue delay.