The protection against corrosion of the pipelines of the Crossbridge refinery in the West of Denmark is described in this paper. During years the pipelines in this refinery suffered significant external corrosion despite a Cathodic Protection, CP, system was in place to protect two different environments, onshore and offshore, from one sole location. Of all the pipelines being under cathodic protection, one suffered from severe corrosion at specific locations. Initially, the CP system was intensively evaluated with the outcome that a replacement of the pipeline was the best option. However, only after detail investigation of the process, the installation of online ER-probes to monitor current, potential and corrosion rates and the evaluation of the foreign pipelines the possible issues were identified. Environmental conditions, soil and sea water resistivity, flow temperatures and foreign district heating pipeline all affected the corrosion of the largest of the export pipeline, a 24” pipeline. Conclusions of the investigation, updated design and mitigation measures will be described in this paper.