Contractors charged with cleaning the most contaminated site at Rocky Flats found five radioactive “hot spots” outside the established cleanup perimeter in recent months, according to U.S. Department of Energy officials.
The discovery led Kaiser-Hill, the company managing the site’s $4 billion cleanup, to conduct additional remediation on soil around the site known as the 903 Pad, the most contaminated site on the 6,500-acre property, DOE Rocky Flats spokesman John Rampe.
As a rule, Kaiser-Hill cleaned any spot found to contain more than 50 picocuries per gram of soil, he said. A gram of soil with that level of radioactivity is estimated to increase a person’s risk of cancer by one chance in a million, he said.
That criteria is “way below the necessary cleanup level” of one chance in 10,000, as designated by the Environmental Protection Agency at other federally funded cleanup sites, Rampe said.
The plutonium- and americium-tainted hot spots around the 903 Pad contained 60 to 70 picocuries per gram of soil, he said.
Workers quickly removed about 75 cubic yards of soil from the hot spots, which were discovered in the past three months, he said.
But on Wednesday, Rampe denied a Daily Times-Call request for soil sample data collected outside the 903 Pad perimeter, saying contractors were still collecting and analyzing the information.
DOE officials will discuss the findings at a Rocky Flats Citizens Advisory Board meeting at 6 p.m. today at College Hill Library, 3705 W. 112th Ave. in Westminster.
Operators at Rocky Flats, which manufactured plutonium triggers for nuclear bombs during the Cold War, stored more than 4,000 barrels of plutonium-contaminated oil on bare ground at the 903 Pad site in the 1950s and 1960s. The barrels leaked, contaminating soil and groundwater.
Officials disposed of the barrels in 1967 and 1968 and laid an asphalt pad over the contaminated dirt in 1969 to stanch the spread of tainted topsoil by intense wind gusts in the area, according to the Colorado Department of Health and Environment.
Since Kaiser-Hill began cleaning Rocky Flats in 1995, workers have hauled away thousands of cubic yards of topsoil tainted by plutonium and americium from the 30-acre 903 Pad site, Rampe said. Americium is a radioactive element produced by decaying plutonium and is more potent than plutonium.
The discovery of the hot spots, which contain radioactive material that was blown outside of the 903 Pad cleanup perimeter by wind, should not alarm the public, Rampe said. Kaiser-Hill’s cleanup project is still set to wrap in October.
“These are very small areas that slipped through the cracks,” Rampe said.
It’s difficult to compare plutonium and americium traces at Rocky Flats to everyday sources of radiation, such as microwaves or potassium in bananas, said Niels Schonbeck, a biochemistry professor at Metropolitan State College in Denver who has researched Rocky Flats.
But the DOE and Kaiser-Hill invariably downplay the danger of contamination at Rocky Flats, he said.
“The people who are cleaning up want to do it for the lowest amount of money and be credited with cleaning up the site,” he said. “They're going to understate those effects.”
The 903 Pad is not included in the part of Rocky Flats slated to become a federal wildlife preserve. But the discovery of the hot spots is proof that the area should not be opened to the public after Kaiser-Hill declares the project finished, Schonbeck said.
“If you look hard enough, you’ll find them in other places,” Schonbeck said.
A Kaiser-Hill spokesman could not be reached for comment Wednesday.
Rampe said the DOE will make sure any hot spots discovered in the future are cleaned up, whether Kaiser-Hill is still involved in the project or not.
Brad Turner can be reached at 720-494-5420, or by e-mail at