The Chlorofluorocarbon (CFC-11 and CFC-12) water samples from the CTD-bottle-system were stored in glass ampoules without contact to the atmosphere during the tapping. Immediately after sampling the ampoules are flame sealed after a CFC free headspace of pure nitrogen had been applied. Along the Greenwich Meridian 36 stations were sampled, along the section between 0° and the GeoBox thirteen stations, in the GeoBox six stations and along 23°E 14 stations. Overall 1007 water samples for CFCs were taken, of which 765 samples were analyzed successfully.The loss of CFCs into the headspace is considered by a careful equilibration between liquid and gas phase under controlled conditions before the sealed ampoules are opened and a precise measurement of the volume of the headspace. The determination of CFC concentrations in the IUP Bremen gas chromatography lab is accomplished by purge and trap sample pre-treatment followed by gas chromatographic (GC) separation on a capillary column and electron capture detection (ECD). The system is calibrated by analyzing several different volumes of a known standard gas. CFC concentrations are calibrated on SIO98 scale (Prinn et al., 2000, doi:10.1029/2000JD900141). A more detailed description of the measurement system is given by Bulsiewicz et at. (1998, doi:10.1029/98JC00140).Accuracy (i.e. uncertainties of calibrated sample volume, calibration curve, extraction efficiency, standard and working gas, water blank, etc.):- CFC-12 < 1.5 %- CFC-11 < 2.0 %CFC measurements: Klaus BulsiewiczThe tracer data set was carefully checked for accurate measurements and outliers. Quality flags: ? = doubtful; / = bad; # = mean of replicates.