‘Better than it was’: Creek, DuPage River removed from Superfund cleanup list after decades of work

Smallmouth bass swim in the West Branch of the DuPage River as it flows through McDowell Grove Forest Preserve near Naperville.

Native plants are thriving along the riverbanks. Kayakers and canoeists enjoy paddling the waterway.

There’s no sign today that this stretch of the river was once part of a nearly $150 million effort to remove radioactive thorium from it and one of its tributaries — Kress Creek in West Chicago. The contamination originated from the former Kerr-McGee factory site in West Chicago.

The cleanup and restoration, which took years to complete, was a massive undertaking “to give our residents the future of clean water and the rebirth of this area that is truly remarkable,” said DuPage County Board member Jim Zay, who chairs the county’s stormwater committee.

“It was a pretty impressive (project),” added Erik Neidy, natural resources director for the DuPage County Forest Preserve District.

Zay, Neidy and other local officials gathered earlier this month to celebrate the official end of the Kerr-McGee Kress Creek project and its removal from the U.S. Environmental Protection Agency’s list of Superfund sites.

EPA-HQ-OLEM-2025-3819-0009_content (3).pdf

“Cleaning up a site like this takes persistence, science, and partnership — and today’s milestone shows the payoff of that work,” EPA Region 5 Administrator Anne Vogel said in a written statement. “The result is a safer community, a healthier environment, and new opportunities to support families, recreation, and economic growth for years to come.”

The history

Sediment, banks and flood plain areas along nearly 7 miles of the creek and river were added to the EPA’s list of Superfund sites in 1991. It joined three other sites in West Chicago that were contaminated by waste from the former Kerr-McGee factory.

The factory, originally operated by Lindsay Light and Chemical Co., began producing thorium and rare earth compounds in 1932. The company made gaslight mantles. Later, the U.S. government purchased the elements for federal atomic energy programs, according to the EPA.

The manufacturing process created a sandlike byproduct called mill tailings, which were stored in large piles on the factory site and made available as free filler material from the 1930s through the 1950s.

According to the EPA, the radioactive material was used for landscaping and building projects before it was determined to be hazardous.

Meanwhile, stormwater runoff was discharged over the years into nearby Kress Creek, which empties into the West Branch of the DuPage River.

Kerr-McGee Chemical Corp. bought the factory in 1967 and closed it in 1973.

The company originally sought to bury waste on site. But after years of legal haggling, it was agreed that the factory site, the West Chicago sewage treatment plant, Reed-Keppler Park and many residential properties had to be cleaned up, starting in the mid-1980s.

The contaminated soils were dug up and shipped to disposal sites in Nevada, Texas and Utah.

Work on Kress Creek and the river began later, and the project picked up steam after a 2005 federal consent decree.

“We fought because thorium had gotten into the creek and the river,” Zay said. “It wasn’t easy, because they (Kerr-McGee) didn’t want to clean up the creek or the river.”

Zay recalled seeing maps that highlighted where dangerous deposits were found, with red marking the heaviest concentrations. The impoundments behind dams in Warrenville and at McDowell Grove were red, he said.

Cleaning a river

According to the EPA, the project divided the site into several sections, from West Chicago to the McDowell Dam near Naperville.

Working upstream to downstream, crews removed contaminated material from each section before restoring areas with clean backfill and vegetation, officials said. Contaminated material was transported off-site for safe disposal.

The EPA said the cleanup was completed in 2014, with restoration and monitoring of the restoration continuing until 2025.

The forest preserve district owns the majority of the land along the banks of the river in that area, Neidy said, so “we had a major stake in assisting” the cleanup and restoration.

Accessing the deposits in the DuPage River required dewatering the sites (redirecting the river’s flow) so workers could get to them, according to Neidy.

When that was done, some things were discovered — including beds of several hundred freshwater mussels.

The forest preserve district saved those mussels from being scooped up, crushed and thrown away. Instead, it started breeding them, launching the district’s aquatic conservation program, Neidy said.

The cleanup also enabled the district to improve the river experience, Neidy said. The district installed rocks and riffles, and to make canoeing and kayaking more interesting.

It also planted thousands and thousands of native plants.

“If you go out to that area, it’s beautiful,” Zay said. “It’s better than it was. It’s a functioning ecosystem that’s great.”

ssarkauskas@dailyherald.com