Vinyl, also known as PVC, is made from two building blocks, chlorine derived from common salt, and ethylene derived from natural gas. 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 simply “vinyl.”