A colorless, flammable gas, ethylene is the largest-volume petrochemical in the world. Ethylene has a number of uses, including the production of plastics such as polyethylene (PE) and polyvinyl chloride (PVC). Chevron Phillips Chemical is a top ethylene manufacturer in North America. Ethylene is mainly produced through the steam cracking (steam pyrolysis) of hydrocarbon feedstocks. Feedstocks used for steam cracking range from ethane to naphtha and gas oils. Some ethylene is also produced as a byproduct of petroleum refining.