Article 23 4.

Where the competent authority of dispatch becomes aware that a shipment of waste referred to in Article 4(4) or (5), or its recovery, has not been completed as intended and that the obligations to take the waste back or arrange for its alternative recovery in accordance with paragraph 1 have not been fulfilled, the competent authority of dispatch shall take all necessary measures to ensure that the person that has arranged the shipment takes the waste back or arranges for its recovery in an alternative way and ensures, if necessary, that arrangements are made for the safe storage of the waste pending its return or non-interim recovery or non-interim disposal in an alternative way. Where it is impracticable for the person that has arranged the shipment to fulfil the take-back obligations, those obligations shall be fulfilled by a person deemed to be the person who arranges the shipment in accordance with paragraph 5 or 6, where relevant.