Low smoke zero halogen (LSZH or LSOH) is a material classification typically used for cable jacketing in the wire and cable industry. LSZH cable jacketing is composed of thermoplastic or thermoset compounds that emit limited smoke and no halogens when exposed to high sources of heat or flame. In fires, a halogen containing plastic material release hydrogen chloride, a poisonous gas, which forms hydrochloric acid when it comes in contact with water. Designated Halogen-free cables, on the other hand, does not produce a dangerous gas/acid combination or toxic smoke when exposed to a flame.