On December the 12th, 2016, a Se-75 source was inadvertently damaged during re-pair work on faulty radiography equipment. The work was performed in Düsseldorf region in North Rhine-Westphalia by a specialized company within a controlled area. The source contained about 1.3 Terabecquerel Se-75. The radioactive substance was released during the repair work and contaminated persons and zones within and out-side of the controlled area. Besides the two workers performing the repair work, other persons were also contaminated. The contamination was spread to pathways outside of the building, but within the site, clothings and private cars. In total more than 80 persons have been tested for intake of Se-75. Committed effective doses greater than 1 mSv were measured for three workers; the maximum dose was well beneath the allowed annual doses limit for workers of 20 mSv (between 1 and 3 mSv). The maximum doses for persons of the general public were in three instances slightly above the yearly dose limit of 1 mSv as specified in the German radiation protection ordinance, in 6 further instances the doses were slightly below 1 mSv. The event was rated INES level 2 because of the accidental release of radioactive substances.