Fertilizer spill near Fort Madison reaches tributary feeding Mississippi River

FORT MADISON, Iowa (KWQC) - The Iowa Department of Natural Resources is investigating a liquid fertilizer spill at a facility near Fort Madison that reached a tributary of the Mississippi River.

State environmental officials were notified Monday of the release of UAN (urea ammonium nitrate), a 32% nitrogen liquid fertilizer, from an on-site containment tank at the Merschman Fertilizer facility in Lee County.

According to the DNR, facility staff noticed a tank leak in early October and began transferring the chemical to a backup tank inside a secondary gravel and poly-lined containment berm. However, following recent rain over the past month, workers used a sump pump to clear liquid from the area, inadvertently pumping an unknown amount of fertilizer and rainwater over the berm.

The mixture entered a drainage ditch south of the property that feeds into an unnamed tributary emptying into the Mississippi River.

Cleanup efforts are underway. Workers are pumping the remaining mixture into an alternate storage tank, and temporary dams have been installed at multiple points along the tributary.

DNR officials reported no dead fish have been observed so far, and water samples have been collected for testing.

The investigation remains ongoing, and residents are asked to avoid the area.