An optical fiber or electrical power cable with at least one electrochemical chemical analyte sensor which includes a conductive polymer which extends longitudinally along the length of the cable. The polymer has electrical properties which undergo a reversible change when in contact with a chemical analyte. The conductive polymer can be a conductive polymer composite including an immiscible polymer blend of at least two polymers and a conductive filler which is dispersed in one of the polymers of the blend through a multiple percolation process. The cable has a jacket and the sensor(s) are disposed outside the core in proximity to an inner or outer surface of the jacket, or as part of the jacket, and not energy coupled to any energy converging media in the cable, so that the presence of analytes in contact with the cable can be detected, the location along the longitudinal length of a cable where the cable is exposed to the analytes can be determined, penetration of the analytes into the cable occurs can be detected, whether damage has been caused to the cable by the analytes or otherwise can be determined and the identity of an analyte which is in contact with the cable can be determined.