A leakage-sensing device for installation adjacent to a pipeline configured for conveying liquid or gaseous chemical materials. The leakage-sensing device comprises a length of cable configured to transmit and back-reflect signals. The cable is communicable with a signal-measuring device. The entire length of cable is encompassed by a torsioned and tensioned coiled biasing means. The cable and the torsioned and tensioned coiled biasing means are embedded in a chemically frangible casing material. The chemically frangible material is selected for its structural instability when contacted with the selected chemical material to be conveyed within the pipeline thereby releasing the torsioned and tensioned biasing means which subsequently imparts bending and/or twisting and/or elongating and/or contracting forces to the cable thereby causing the cable to physically interfere with and/or deform and/or break the transmission and back-reflection of signals along the cable.