Someone's got to build the building blocks: Equistar Chemicals, a subsidiary of LyondellBasell, does that by manufacturing chemical building blocks. Its primary product is ethylene, which is the world's most-used petrochemical and the basis for any number of other chemicals, plastics, and synthetics. Among the company's other products are propylene, butadiene, polyethylene, polypropylene, ethylene oxide, ethylene glycol, benzene, and toluene. Polyethylene is used in plastic bags and bottles; polypropylene is used in plastic caps, rigid packaging, automotive components, and carpet.