OSCEOLA — Officials are investigating a grease spill in southern Iowa that’s been linked to a fish kill. The state Department of Natural Resources says Osceola Foods, a food processor in Clarke County, reported Sunday morning that a pumping station failed. As a result, grease-water mix spilled into a ditch that leads to White Breast Creek, south of Osceola. Officials believe the mixture may reach the creek. DNR says the mixture left small dead fish along a 1,500-foot stretch of the ditch.