Vinyl chloride is a colorless, flammable gas with a sweet odor that is used to make polyvinyl chloride (PVC) plastics and polymers. It has a chemical formula of C2H3Cl and molecular weight of 62.5 g/mol. Exposure can occur through factory emissions, evaporation from waste sites, or off-gassing from new plastic products. Vinyl chloride is carcinogenic and toxic, especially to the liver, kidneys, and central nervous system. A 2004 explosion at a Formosa Plastics plant in Texas released vinyl chloride, ignited an explosion, and caused fires that burned for days after the accident.