Boulder, Colo.-- Additional trace amounts of contamination have been found in the office and a nearby stairway used by a laboratory researcher originally exposed in an incident June 9 involving a small amount of plutonium-containing powder at the Commerce Department's National Institute of Standards and Technology. The soles of the shoes of the researcher's officemate also showed trace contamination, which was cleaned. The contamination was found today and late last night during a detailed survey of the areas based on additional interviews with personnel involved.
The office is in a different hallway than the original laboratory room where the incident occurred. The survey showed trace amounts of contamination on one desk, a lab notebook on that desk, and the chair associated with that desk, that had been used by the originally affected researcher. As a precaution, the office has been sealed until more thorough testing and evaluation can be completed.
The trace contamination found on the stairway has been cleaned.
The hallway areas adjacent to the affected office have also been surveyed. No evidence of removable contamination beyond normal background levels has been detected.
Radiation health effects from plutonium primarily come from alpha particles. The radiation emitted by alpha particles does not penetrate the skin. Adverse health effects from plutonium exposure occur with ingestion or inhalation of the particles.
On June 11 two more personnel at NIST identified themselves as being potentially exposed to the powder in addition to 22 people originally identified; however testing so far has shown no contamination of these additional individuals.
NIST employees and associates have been given updated information about the incident. NIST is conducting an investigation and the Nuclear Regulatory Commission (NRC) has previously been notified. An investigator from the NRC visited NIST and offered advice for the continuing investigation.
For reference, the text of a news release issued on June 10 follows.
Additional information on the NIST Boulder plutonium incident is available online.