Operator error leads to nearly 10,000 gallons of sanitary sewage spilling into Milwaukee's Lincoln Creek Tuesday. The Metropolitan Milwaukee

The Milwaukee Metropolitan Sewerage District said a contractor accidentally released nearly 10,000 gallons of sewage into Lincoln Creek.

Workers from Veolia Water Milwaukee discharged approximately 9,600 gallons of sanitary sewage from a vacuum truck into a storm sewer that the crew "mistakenly believed was a sanitary sewer."