About a mile from homes in Missouri’s St. Louis County lies a radioactive hot spot with contamination levels hundreds of times above federal safety guidelines. But there are no plans to clean it up.  That is because the location, tainted with waste from atomic-weapons work done in local factories decades ago, has been deemed by the federal government to be effectively inaccessible and not a threat. The site, which runs along and underneath a railroad track, is far off the beaten path and the contamination is covered and anchored in place, said Bruce Munholand of the U.S. Army Corps of Engineers, which is removing weapons-related waste at dozens of sites in the St. Louis area.

However, a group of private researchers funded by an environmental activist, including a former senior official of the Clinton administration’s Energy Department, is challenging those assurances.  They say a recent sampling they did suggests contamination from the radioactive hot spot is entering a nearby stream, known as Coldwater Creek, and then traveling downstream into the yards of homes. The contamination involves thorium, a radioactive material that can increase a person’s risks for certain cancers if it gets inside the body, according to the Environmental Protection Agency.

The dispute over the hot spot is part of a larger debate nationally over the radioactive legacy of the nuclear-weapons program. With dozens of locations being cleaned up, one question is how much contamination can safely be left behind. In many of these sites, cleanup issues involve how accessible particular locations are to the public and what future uses might be.

Some of the St. Louis weapons-related waste was stored for a time in piles above ground. Portions of it were eventually dumped in a landfill in the area, where heated arguments continue over what to do with it. Some waste simply fell off trucks and railcars as it was being transported.

Dr. Kaltofen and his fellow researchers—Robert Alvarez, the former Energy Department official, and Lucas Hixson, a nuclear researcher in Michigan—recently did a study regarding possible off-site contamination from that local landfill, known as West Lake. Published in the peer-reviewed Journal of Environmental Radioactivity, the study was funded by a St. Louis-area environmental activist.

In doing further work in the area, “we followed a breadcrumb trail of microscopic particles upstream from the residential neighborhoods and found this hot spot,” said Dr. Kaltofen. Sampling found levels of radioactive thorium at up to nearly 11,000 picocuries per gram, some 700 times the federal cleanup standard of 15 picocuries per gram being used by the Corps…. If contamination is still getting into Coldwater Creek and being carried into yards during floods, the hot-spot’s level of contamination and proximity to the stream makes it a prime suspect, he argued.

Excerpt from Radioactive Hot Spot Prompts Researchers’ Concerns, Wall Street Journal, Apr. 28, 2017