Additional soil samples from the Rocky Flats National Refuge did not test positive for elevated levels of plutonium, according to the test results released Thursday.
The highest result among the soil samples was 2.90 picocuries per gram, well below the federal guideline of 50 picocuries per gram for the former nuclear weapon manufacturing site, the results said. A soil sample tested from the site in August indicated levels of 264 picocuries per gram.
But after 25 additional soil sample tests from the same area, the result from August "appears to be an outlier," said Laura Dixon, spokeswoman for the Colorado Hazardous Materials and Waste Management Division.
The results of the latest soil samples were similar to dozens of other samples tested from the area in recent months, according to the Denver Post.