The US Nuclear Regulatory Commission is investigating a reported incident in which a cracked vial holding a small plutonium sample was discovered by researchers in a lab at the Commerce Department's National Institute of Standards and Technology (NIST) campus in Boulder, Colo.The sample was being used in a research project to develop improved radiation detectors. The researchers discovered the cracked vial Monday. Some particles had spilled from the vial, which held about one-quarter of a gram of a plutonium-containing powder, the NIST said in a statement. The laboratory room and an adjacent lab were sealed off, and some of the 22 NIST staff and associates who had been working in or near the lab had trace contamination on their shoes or clothing which was cleaned with soap and water. Two who worked directly with the plutonium washed trace contamination from their hands. Contimination was also cleaned from a nearby hallway, the NIST said."Air sampling in the affected laboratory room shows no evidence of airborne plutonium particles," the NIST added. "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 NIST said. Those affected being monitored to quantify any potential individual exposure from the plutonium. "Based on continuing test results, appropriate actions will be taken if necessary," the NIST said.For more information, visit: nist.gov