The chemistry is complicated but in a nutshell organohalogens occur in nature.Organohalogens, are the group of compounds that contain a halogen atom (fluorine, chlorine, bromine, or iodine) bonded to a carbon atom. Vinyl Chloride – an organohalogen and the monomer used in the manufacture of PVC – is a natural soil product.

Like all plastic materials, PVC/vinyl results from a series of processing steps that convert hydrocarbon-based raw materials (petroleum, natural gas or coal) into unique synthetic products called polymers. The vinyl polymer is unusual, however, because it is based only in part on hydrocarbon feedstocks: ethylene obtained by processing, or cracking, natural gas or petroleum. The other half of the vinyl polymer is based on the natural element chlorine.

Chlorine gives vinyl two advantages. First, chlorine is derived from brine -- a solution of common salt and water, and a readily available, inexpensive commodity. Thus, vinyl is less sensitive to fluctuations in the world oil market than are totally oil dependent polymers.

Second, chlorine has excellent inherent flame retardant properties. These properties are passed on directly to vinyl end-products, making vinyl an excellent choice for applications such as electrical conduit and wiring that require high resistance to ignition and flame spread.

Through a chemical reaction, ethylene and chlorine combine to form ethylene dichloride which, in turn, is transformed into a gas called vinyl chloride monomer (VCM). A final step, called "polymerization," converts the monomer into vinyl polymer, a fine-grained, white powder or resin known as polyvinyl chloride (PVC) or "vinyl."

PVC resin, however, is still one step away from being a usable material: it must be combined with selected chemical additives and modifiers to achieve the various properties desired in vinyl end-products. Once these are added, the resulting material -- vinyl compound -- can be converted into an almost limitless range of applications. (View the above diagram of the vinyl production process.)

This versatility is yet another reason why PVC claims such a large share of the plastics market. It is the only plastic that can be made thin and flexible enough for wallcoverings, yet rigid and tough enough for siding on buildings. Depending on the additives and modifiers used, vinyl compound can be used indoors or outside, be crystal clear or opaque, and matched to virtually any color in the rainbow.