Officials say initial lab tests indicate that a wastewater spill into the Big Sioux River won't affect people or wildlife.
Sioux Falls Public Works officials say they're continuing to monitor the river and expect more test results later in the week.
The city in a statement says about 9,000 gallons of "treated biosolids" made it into the river Sunday before the spill at the water treatment plant was contained with an earthen berm. Wastewater Superintendent Mark Perry says biosolids are solid organic materials from treated sewage.
He says treated biosolids have a high ammonia content but river water tests have come back normal.
The contractor responsible for the spill - Veit, of Rogers, Minnesota- is working to clean up the spill area. That's expected to take through Wednesday.
This article has been revised to reflect the following correction:
A misspelling was corrected in this story.