Information Update: Additional Trace Contamination Found in NIST-Boulder Lab

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:

Low-Level Plutonium Sample Involved in NIST-Boulder Lab Incident

Boulder, Colo.- On Monday afternoon, June 9, researchers in a laboratory room at the Commerce Department's National Institute of Standards and Technology (NIST) campus in Boulder, Colorado discovered that a vial holding about 1/4 gram of plutonium in a powdered form had cracked* and that some particles had spilled from the vial. The laboratory room and an adjacent lab in NIST's Building 1 were immediately sealed off. Twenty-two NIST staff and associates who had been working in or near the lab were asked to remain in the immediate area until they could be carefully monitored and any radioactive materials on their clothing or bodies removed.

Trace contamination was found on the soles of the shoes or on a few articles of clothing for most of the 22 personnel. In most cases, the trace contamination was easily removed using soapy water following standard health physics practices, and 20 personnel were sent home contaminant-free. Two staff members who had worked directly with the material had trace contamination on their hands and began the standard health physics practice of carefully washing their hands to remove the contamination.

NIST health safety personnel supervised the careful testing of nearby hallways and adjacent labs and offices. Some areas of trace contamination were found in the nearby hallways and in a small office area at the end of a hallway. These areas were cleaned and retested to ensure they were contamination free. There was no evidence of any contamination outside of the immediate area or in the doorways leading out of the building.

The affected laboratory room and the adjacent connecting laboratory room were sealed off for further testing, along with the nearby men's room. These areas will be fully assessed and cleaned as required. Air sampling in the affected laboratory room shows no evidence of airborne plutonium particles. There is no evidence that any radioactive materials left the affected laboratory, apart from the trace contaminants in nearby areas and on the affected personnel, and all those traces have been thoroughly cleaned and the areas retested, showing no radiation above normal background levels.

Plutonium is a radiation-emitting element, and the research sample involved is a certified reference material with very precisely known radiation activity levels. The affected NIST employees and associates are being carefully monitored to quantify any potential individual exposure from the plutonium. Based on continuing test results, appropriate actions will be taken if necessary.

The small plutonium sample (smaller than a dime in size) was being used in a research project to develop improved radiation detectors for use by nuclear inspectors outside NIST. The Nuclear Regulatory Commission has been advised about the incident. NIST is conducting a thorough investigation to gather facts about how the incident occurred and to determine what, if anything, may be done to prevent any similar situations in the future.

NIST employees have been given information about the incident.

*Corrected July 17; the sample included 1/4 gram of plutonium in the form of 0.53 gram of plutonium sulfate tetrahydrate.

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Created: 06/10/2008
Last updated: 07/17/2008
Contact: inquiries@nist.gov