Most commercial plastics are synthetic polymers derived from petrochemicals. They are analogous to petrochemicals derived from petroleum. Hydrocarbons are used as fossil fuels and to manufacture plastics and petrochemicals. The IOB trades petroleum, petrochemicals and gas in various currencies. VCM is among the top twenty largest petrochemicals (petroleum-derived chemicals) in world production. He recognized the importance of petroleum as a feedstock for petrochemicals. Paper, rubber, plastics, petrochemicals, carbon insulators, and abrasives composed the city's major industries. It also drove an enormous expansion in refining, petrochemicals, chemicals and engineering. New industries include the production of fertilizers and petrochemicals. Oilseed can be modified to produce fatty acids for detergents, substitute fuels and petrochemicals. In contrast, the feedstocks for polymers derived from petrochemicals will eventually deplete. The city's main industries include machine manufacturing, petrochemicals and oil refining, and electronics. Industry remains the most important employer, notably in the pharmaceuticals, petrochemicals and food processing. There are many concerns about the life cycle of synthetics, which come primarily from petrochemicals. Other industries include textiles, footwear, fashion and apparel, packaging, machinery, paper and petrochemicals.