Up to 16,000 gallons of waste oil might have spilled through two culverts into the North Raccoon River. The spill was reported Thursday afternoon the the Greene County Sheriff&rsquo;s office and the Iowa Department of Natural Resources began cleanup efforts that same day.<span style="font-size: xx-small;"><em>&nbsp; Daily Times Herald photo by Jeff Storjohann</em></span>
Up to 16,000 gallons of waste oil might have spilled through two culverts into the North Raccoon River. The spill was reported Thursday afternoon the the Greene County Sheriff’s office and the Iowa Department of Natural Resources began cleanup efforts that same day.  Daily Times Herald photo by Jeff Storjohann
Tuesday, September 18, 2012

JEFFERSON — Workers have contained a large oil spill reported late last week to a 15-mile stretch of the North Raccoon River that runs from the southwest side of Jefferson to near Squirrel Hollow Wildlife Area, southeast of town.

An oily sheen covers the surface of the river with patches of black where the oil has collected in pools and behind the absorbent tubes workers placed across the river to stem the pollution since Thursday.

About 6,000 gallons of oily water have been pumped from the river, said Alison Manz, of the Iowa Department of Natural Resources, who oversees the cleanup that could go on for weeks.

It’s still unclear how much oil leaked from a 20,000-gallon storage tank at Krieger Greenhouses on the west side of Jefferson, Manz said.

About 4,000 gallons remain in the tank, but Ernie Krieger, the owner, said today that he doesn’t know how much oil it held before the spill. He estimates that between 50 and 500 gallons leaked from the tank, but Manz thinks the amount is much higher.

Manz will be able to estimate the size of the spill by separating the oil from the contaminated water taken from the river.

Kurt Krieger, operations manager for the business, told the Jefferson Bee on Monday that the tank was somewhere between one-quarter and half full. The tank holds waste oil that is burned for heat.

A valve on the tank was slightly ajar, which allowed the oil to trickle out, Ernie Krieger said.

“We think it was just an animal that went through — a ’coon maybe — and knocked the valve,” he said. “If it was vandalism, they would have opened the valve all the way.”

Krieger described the spill as “no big deal” on Friday in a brief interview with the Daily Times Herald, but he acknowledged today that the cleanup will be arduous.

Workers made a series of dams in a ravine between Krieger Greenhouses and the river — a stretch of several hundred yards — to stop any more oil from reaching the river. They removed oil that collected in a thick, 3-feet-deep pool near the river and tore out the contaminated ground.

No fish have been found dead from the oil, Manz said.