Hilex Poly Co., the world's largest plastic bag company, said recently that it will close a plant in Mount Olive and put about 160 employees out of work. The company, based in Hartsville, S.C., is reducing production capacity as demand for plastic bags wanes. Consumers and retailers are becoming more environmentally conscious and turning to reusable bags to carry groceries and goods. Cities such as San Francisco have banned plastic bags altogether. In January, Seattle will begin charging a 20-cent fee on each one of them. Stores such as Wal-Mart and REI have introduced canvas bags that shoppers can use multiple times. Hilex, which traces its history to 1980, filed for bankruptcy in May, blaming rising prices for resin and "tightened trade terms." Hilex emerged from Chapter 11 protection in July. Hilex expects to begin laying off workers at the plant soon, according to a notice filed recently with the N.C. Department of Commerce. The cuts will take place during a two-week period, it said.