ST. CHARLES, MO.– Take a hike up the Nuclear Waste Adventure Trail. This radioactive cleanup site is open to visitors.

The Weldon Spring Site is located in St. Charles County, 30 miles west of St. Louis. It used to be the site of the 1956 Weldon Spring Chemical Plant.

Behind the welcome center is a large mound that looks like it is made out of rocks.

“From 1966 to 1987/1989 is when the site was added to the National Priority List,” Kevin McCarthy, Education Programs Manager, said.

The National Priorities List (NPL) is the list of national priorities. These sites may contain hazardous materials.

“The army did some cleanup along the way, it was surplus government property at the time,” said McCarthy.

Weldon Spring Chemical Plant got added to the national list. Different government regulators and stakeholders started a cleanup plan. They started assessing the hazardous site.

“It’s easy to say ‘go and clean it up.’ But you first have to know what you are dealing with, you have to then plan the work, you have to know then what you are going to do with the cleanup, and you have to know where the waste is going to go,” said McCarthy.

McCarthy said there are records of decisions that the cleanup team had to document. This documentation is available in the Visitor Center on the site.

“So what you see outside, that is where the waste went,” said McCarthy. “Inside there is all the building rubble and debris. Everything from the building is in there.”

McCarthy showed a cut-a-way of the cell and in the diagram, there are the bottom layers of the cell, the waste, and then the top layers of the cell.

“It was designed, it was taken into the account the largest amount of rainfall this region could see, it was taken into account earthquakes,” said McCarthy.

McCarthy said there is a multi-layer membrane that sits overtop of the clay, so it sheds water like an umbrella.

The Weldon Springs Site Interpretive Center does offer tours and educational programs. Once the stairs are fixed, the public can explore the site.

Currently, there are no stairs up to the mound. The goal is that the new stairs will be replaced sometime next month. The mound is the largest peak in St. Charles County.

Brief History

The site opened up to the public after the clean-up in 2001.

McCarthy said before there was a nuclear cleanup site, the place was farmland then it became wartime factory in and around 1940.

“In the 1930s and even before, that whole land was homesteaded,” McCarthy said. “The lands were taken over by the army in 1940 to make way for the world’s largest TNT and DNT explosive production plant.”

“While this site was processing TNT and DNT for World War II, there was a whole other scientific process that was evolving around nuclear weapons,” McCarthy said.

The threat from Nazi Germany and nuclear scientific research, caused the Manhattan Project to begin. It was the start of the U.S. nuclear arms program.

“The Weldon Spring site was not a Manhattan project site, but downtown St. Louis Mallinckrodt Chemical Company at the time at the Destrehan Street plant location, was a Manhattan project site,” said McCarthy.

McCarthy said the St. Louis Mallinckrodt Chemical Company processed uranium ore. They then shipped it off to other facilities for enrichment. The uranium was eventually used for weapons.

Enriching uranium into weapons-grade plutonium causes radioactivity that is harmful to the environment.

Uranium starts as an ore. It is transported to a mill where it is crushed and undergoes a chemical process to remove the uranium. The uranium is then concentrated to produce a material called “yellowcake” for its yellowish color.

The yellowcake is then transported in barrels to the factory to be processed.

“This is not pure uranium, but it is closer to it. With any uranium processing, dust is the direct pathway into the human body. Dust is a challenge and can be a safety risk,” said McCarthy, talking about yellowcake.

The Weldon Spring Site, the goal of this site was to create uranium metal.

“So the uranium production plant operated from 1957 to 1966, the cold war era,” said McCarthy.

“So before 1970, there was no EPA,” said McCarthy. “Once the environmental protection act comes in then we get the National Environmental Policy Act, Clean Air Act, Safe Drinking Water Act.”

The National Environmental Policy Act (NEPA) was one of the first laws ever written that established a broad national framework for protecting the environment.

“All that to say, before 1970, anything that happened in the environment, nobody was breaking any laws,” said McCarthy. “It is easy to step back in time and judge it, but it was just how it was at the time.”