Iowa DNR investigating fertilizer spill

The Iowa Department of Natural Resources is investigating how a liquid nitrogen fertilizer spill was handled last Thursday in a northeast Iowa community,

An employee of the Farmers Cooperative in Allison was pulling a tank of 32 percent liquid nitrogen fertilizer through the Butler County community when a seam on the tank failed. About 800 gallons of the fertilizer spilled on a city street.

Without reporting the spill to the DNR, Farmers Cooperative employees decided to wash the spilled liquid into a storm sewer.

The DNR was notified of the fertilizer spill on Friday morning, 26 hours after the accident happened. The agency advised Farmers Cooperative to flush the storm sewer with water and pump out the mix of water and fertilizer to prevent additional fertilizer from reaching a nearby stream. They also were asked to soak up any standing liquid on the street.

When DNR staff arrived Friday afternoon, they found dead minnows for about a half-mile downstream of the storm sewer. Water samples over the eight mile stretch of stream to the West Fork of the Cedar River showed elevated levels of ammonia in spots, but ammonia levels dropped significantly over the next three days.

By Monday afternoon, no additional dead fish were found.

The DNR asked Farmers Cooperative on Saturday to build a dam across a drainage ditch south of Allison to collect additional contaminated water. By early Monday afternoon, the cooperative had recovered about 42,000 gallons of the water-fertilizer mix.

The DNR plans to continue to monitor cleanup of the fertilizer and consider appropriate enforcement actions.