The Iowa Army Ammunition Plant in Middletown has discharged an estimated 100,000 gallons of untreated wastewater over the last two days.
The release was reported to the DNR Wednesday morning, but began Monday afternoon when a pump in the wastewater treatment plant failed. Wastewater flowed from the plant to an unnamed tributary of the Skunk River and then to the Mississippi River. The unnamed creek is mostly on the ammunition plant's land.
Plant operators repaired the pump and stopped the flow about 8 a.m. Wednesday morning.
The plant is located 10 miles west of Burlington and manufactures munitions.
The DNR will issue a notice of violation for failure to report the discharge within 12 hours.