On 21st January 2019 a well-logging geophysical probe containing radioactive source was dropped to the bottom of a1800 m deep well near Pecs city, Hungary. The cause of the event was the break of the probe head due to material failure. The license holder responsible for handling the radioactive source and performing the well-logging probe informed the regulatory body about the event on 22nd January 2019. The successful retrieval of the sealed source was only possible on 6th February 2019, using a modified retrieval technology based on the approval and oversight of the regulatory body with the involvement of a subcontractor licensed for such an activity. The INES 1 level event (anomaly) had no consequences to the environment and to the public.