An 118-year-old factory, the oldest in Anderson, will close today. The PQ Corporation plant at 1900 Columbus Ave. opened in 1889 and once shipped 150 million pounds of raw materials around the country annually. It had more than 88 workers before 1969, when the numbers fell to less than 20, plant coordinator Steve Sheets said. Another round of downsizing in 1997 trimmed staff to eight, and another recent cut made it six. The decision to close the plant came in March, Sheets said. Linda Dawson, Anderson’s director of economic development, said PQ Corporation’s closing in Anderson makes Barber Manufacturing Company the city’s oldest manufacturing business. Barber began operations in 1894.