Medical tests have indicated internal plutonium exposure in a small number of personnel at the National Institute of Standards and Technology (NIST) due to a June 9 plutonium spill in a laboratory room, the institute reported. Trace-level contamination was also found more than two weeks later in a different building. "We are concerned for the health and safety of our personnel and deeply regret these results showing internal plutonium exposure," NIST Deputy Director James M. Turner said in a statement. "We are getting advice from the best medical experts in the country and will do everything we can to ensure that the people affected get the best possible medical treatment." To protect the workers' privacy, the institute said it was not releasing certain specific information about the tests. Researchers at the lab discovered a cracked vial June 9. Some particles had spilled from the vial, which held about one-quarter of a gram of a plutonium-containing powder (See NRC Probes Cracked Vial). 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. Contamination was also cleaned from a nearby hallway, and air sampling showed no traces of airborne plutonium particles. Health concerns from plutonium occur primarily after inhaling or ingesting the radioactive substance. The contamination was detected in urine samples using a technique called alpha spectroscopy. The test detects weak radiation signals from alpha particles, the principal form of plutonium radiation that can cause health effects. In consultation with medical experts, NIST said it has been monitoring the health of the lab personnel who potentially could have been exposed as a result of the June 9 incident. Additional urinalysis testing using thermal ionization mass spectrometry is also being conducted for all personnel potentially exposed. Full results from these tests, which typically detect lower levels of contamination than the alpha spectroscopy tests, are not expected for up to four weeks. Treatment for plutonium exposure consists of receiving one or more injections of a chelating agent that circulates through the bloodstream and attaches to plutonium atoms in the body to allow them to be excreted more easily in the urine. The principal effect of internal plutonium exposure is a potential increased long-term risk of cancer. Removing as much plutonium as possible from the body reduces the risk, according to plutonium health effects experts. NIST also said three small spots of trace-level contamination were discovered June 26 n a different NIST building from the location where the spill occurred. The trace contamination was found on items belonging to an individual who was in the lab after the June 9 spill occurred, but before it was reported, NIST said. NIST said its radiation health experts know of no safety or health concerns from the trace levels of surface contamination. “We are re-interviewing all potentially exposed personnel to determine if any other areas need to be checked to ensure there is no trace contamination remaining,”Turner said. “We are committed to strengthening our safety program and its implementation to help prevent safety incidents in the future,” Turner said. NIST said it will continue to provide updates on the results as they become available. For more information, visit: www.nist.gov