PVC is a thermoplastic made of chlorine (derived from industrial grade salt) and carbon (derived predominantly from oil / gas via ethylene). It is less dependent than other polymers on crude oil or natural gas, which are nonrenewable, and hence can be regarded as a natural resource saving plastic, in contrast to plastics such as PE, PP, PET and PS, which are totally dependent on oil or gas. This chlorine gives to PVC excellent fire resistance: when PVC is set on fire, the flames go out as the fire source is removed due to the material’s self-extinguishing properties.
If a conduit is LSZH (Low Smoke Zero Halogen), it is often referred to as HFT（Halogen Free Tubing）, and is used primarily in tunnels, theaters, shopping centers and anywhere there is a large public presence. The product does not produce toxic fumes or gases and does not release toxic halogens.
PVC conduit is one of the safest and most tested materials used in North America. For over 60 years, every aspect of its production, use and disposal has been evaluated and approved by government and independent certification and testing agencies.
PVC is approved for use around the world in electrical distribution and transmission, consumer products and utilities.
PVC conduit meets or exceeds all required health and safety standards and regulations governed by the U.S. and Canadian Safe Drinking Water Acts and other international statutes. Its use is monitored by independent agencies like NSF International — and government bodies like the U.S. Environment Protection Agency ensure its safety through mandatory regular testing. The U.S. Food and Drug Administration and Consumer Product Safety Commission have confirmed that PVC is a safe product.