A 20-year-old man was killed after he fell into a piece of machinery at the Planters Cotton Oil Mill in Pine Bluff. Marcus Antonio Lowden of Pine Bluff was killed early yesterday. The death was ruled accidental. Planters mill vice president John Jefferson said Lowden was putting seed into the mill when the accident happened. He said no other workers were around him. Police said the two employees who found the remains said they heard something unusual and went to investigate. It was unclear which worker had fallen into the machine. A head count revealed Lowden was missing.