Authorities are investigating how three workers were exposed to radioactive plutonium during environmental restoration work at the Nevada Test Site, a spokesman for the National Nuclear Security Administration said.
Two female workers for the test site's main contractor, National Securities Technologies, received the highest of what NNSA spokesman Kevin Rohrer characterized as "minor radiation exposure" on April 30.
A man received less exposure to the radioactive element, Rohrer told the Las Vegas Review-Journal for a Wednesday report. The three were among eight workers in the area, including a health physicist and technicians. All were wearing protective gear including respirators.
"The exposures are relatively low, but they're high enough that it concerns us," Rohrer said.
The workers remained on the job, but the women were not allowed into radiation areas, Rohrer said. For privacy reasons, the names of the eight workers were not released.
A spokeswoman for the contractor, Gillian Silver, said the company was conducting an internal investigation "to monitor the lessons learned from this experience to make sure any occupational health issues are addressed."
"We don't have any reason to believe there were any security or safety considerations here," Silver said.
Tests showed the women received 400 millirem "effective dose" exposures, while the man had an estimated dose equivalent to 100 millirem, Rohrer said. He said there was no way to predict what effect, if any, the exposure would have on the workers over a 50-year dose monitoring period.
The regulatory standard for radiation workers is 5,000 millirem per year. The test site maintains an administrative guideline of no more than 500 millirem per year. A millirem is one-thousandth of a rem, the unit of dose for ionizing radiation.
(Copyright 2007 by The Associated Press. All Rights Reserved.)