The HalOcAt- database is a data product of the HaOcAt inititative (https://halocat.geomar.de), which was active from 2010 to 2018. The HalOcAt database was compiled as part of the doctoral thesis of F. Ziska at GEOMAR from 2010 to 2018. HalOcAt brought together global oceanic and atmospheric data sets of mainly short-lived brominated, chlorinated and iodinated trace gases, as bromoform (CHBr₃), dibromomethane (CH₂Br₂), dibromochloromethane (CHBr₂Cl), bromodichloromethane (CHBrCl₂), methyl bromide (CH₃Br), methyl iodide (CH₃I), diiodomethane (CH₂I₂), chloroiodomethane (CH₂ClI), bromoiodomethane (CH₂BrI), dichloromethane (CH₂Cl₂), chloroform (CHCl₃) , trichloroethane (C2HCl3), carbon tetrachloride (CCl4), tetrachloroethene (C2Cl4), and higher iodoalkanes (R–I).Many of the data of bromoform (CHBr₃), dibromomethane (CH₂Br₂), and methyl iodide (CH₃I), included in this zip-Archive have been used in the publication of global halocarbon emissions by Ziska, F. et al, 2013. The data and data products are attached as a supplement to the publication.In this HalOcAt data product halocarbon data from ocean and atmosphere were formatted into a uniform Excel template, which consists of three sheets. The first sheet contains the Metadata , the second and third sheet seawater, respectively air data, if available, with the columns: Sample Identifier, Sampling Gear, Date (UTC) and time, (Air sampling period), Sample start latitude (+ve N), Sample end latitude (+ve N), Sample start longitude (+ve E), Sample end longitude (+ve E), Sample depth (meter), Bottom Depth (meter), Water Temperature, in situ (°C), Water Salinity, CH3I (pM), CH2I2 (pM), C2H5I (pM), C3H7I (pM), C4H9I (pM), CH3Br (pM), CHBr3 (pM), CH2Br2 (pM), C2H5Br (pM), CH3Cl (pM), CHCl3 (pM), CH2Cl2 (pM), C2HCl3 (pM), C2Cl4 (pM), CH2ICl (pM), CH2IBr (pM), CHIBr2 (pM), CHBr2Cl (pM), CHBrCl2 (pM), Quality Control CommentsThe HalOcAt- database was curated on a best-effort basis rather than for full coverage. Missing entries are expected and are outside our responsibility. More halocarbon data in ocean and atmosphere from the involved scientists can be found on PANGAEA, other public databases or directly from the scientists.