PVC is commonly used as the insulation on electrical cables such as teck; PVC used for this purpose needs to be plasticized. Flexible PVC coated wire and cable for electrical use has traditionally been stabilised with lead, but these are being replaced with calcium-based systems.
In a fire, PVC-coated wires can form hydrogen chloride fumes; the chlorine serves to scavenge free radicals and is the source of the material's fire retardance. While hydrogen chloride fumes can also pose a health hazard in their own right, it dissolves in moisture and breaks down onto surfaces, particularly in areas where the air is cool enough to breathe, and is not available for inhalation. Frequently in applications where smoke is a major hazard (notably in tunnels and communal areas), PVC-free cable insulation is preferred, such as low smoke zero halogen (LSZH) insulation.