Issue Date: July 28, 2008
THE ACCIDENTAL RELEASE of plutonium at the National Institute of Standards & Technology's Boulder, Colo., campus last month has become a major headache for the agency. All radioactive work at the Boulder facility has been suspended, local officials are demanding more answers, and Congress is questioning the agency's safety and emergency training procedures.
The plutonium release occurred on June 9 on the second floor of Building 1 (C&EN, July 7, page 19). A guest researcher accidentally cracked a vial containing plutonium-239, handled the broken vial and locked it away, washed his hands in the sink, and then walked down the hall to report the incident.
As information about the release has surfaced, members of Congress and others have been raising questions about the adequacy of NIST's reaction to the spill. On July 15, the House of Representatives' Science & Technology Subcommittee on Technology & Innovation, which has jurisdictional oversight of NIST, held a hearing to find out how the incident occurred and what NIST was doing about it.
The tenor of remarks by members of Congress at the hearing was critical. "I am very disappointed that the preliminary investigations of this incident have revealed not just a stunning lack of preparation but also a complete lack of understanding of the potential risks involved in the use of encapsulated plutonium samples," charged Rep. Phil Gingrey (R-Ga.), the senior Republican member of the subcommittee. "This incident is absolutely unacceptable."
Rep. David Wu (D-Ore.), chairman of the subcommittee, said, "These events have revealed serious flaws in the environmental, health, and safety programs at NIST. Initial investigations of recent incidents have found both a lack of training for researchers performing experiments and inadequate laboratory safety policies."
The congressmen aimed their ire at NIST Acting Director James M. Turner, who offered no excuses for the problems surrounding the spill and tried to explain that, as a result of the accident, NIST was already changing its procedures to improve safety training and emergency response. He said that the agency had instituted a new single telephone number to call in case of emergencies and that he was seeking outside help in evaluating NIST's procedures.
"At my request, five eminent experts in radiation health safety conducted an assessment of the incident," Turner said. "Their reports are sobering in their assessment of our challenges, and I take their words very seriously. Their views about our shortcomings confirm my belief of the need to focus our efforts on NIST's entire environmental, health, safety, and emergency response protocols and safety culture."
These experts' assessments are uniformly critical of the response to the plutonium spill, especially the fact that the individuals who were working with the radioactive element were not properly trained in its handling or emergency procedures.
Turner also told the subcommittee that, in light of these assessments, he "issued a stop work order for all radioactive materials in use at NIST-Boulder, and a preliminary decision has been made to limit the use of radioactive materials in Boulder in the future to sealed sources."
Wu asked Turner whether one of the consequences of the spill was going to be termination of some employees, suggesting that making such a decision too quickly could demoralize an already shaken staff. Turner assured Wu that NIST would make no such decisions until all investigations were complete.
NIST, whose main campus is in Gaithersburg, Md., has been quite open with its information on the plutonium incident. Since the accident, the agency has released the reports of its experts' investigations and the preliminary evaluation that it sent to the Nuclear Regulatory Commission (NRC), the federal agency that licenses facilities to work with radioactive materials. NIST has also tried to work with local authorities to address concerns about environmental contamination.
The details of the spill and its aftermath could be a case study for anyone handling radioactive materials. According to NIST, a foreign guest researcher at the Boulder laboratory was investigating new radioactivity sensors that could be used by security personnel. He was using a plutonium reference sample that contained 250 mg of powdered plutonium sulfate and had a total radioactivity of 44.1 millicuries. Most of the sample was plutonium-239.
During his study, the researcher removed the encapsulated sample from its container and tried to position it on a radioactivity detector in a microcalorimetric spectroscopy system. At this time, he accidentally hit the vial, probably on some surrounding lead shielding, and unknowingly cracked the vial's bottom. The fracture must have released some plutonium because the reading on the detector dropped, NIST reported. When the researcher discovered the damaged vial, he returned it to its container and locked it away.
BEFORE WALKING down the hall to notify the principal investigator about the broken vial, however, the researcher moved his notebook to a different table and washed his hands in the laboratory sink, according to NIST. All of these areas became contaminated with plutonium. Once the principal investigator arrived in the lab, he notified the Boulder radiation safety officer and other appropriate response personnel, NIST reported.
Because the room where the plutonium was being used was a multipurpose laboratory, several other lab personnel also became contaminated with plutonium. NIST said in its report to NRC that everyone who had been in the room that afternoon was told to stay in the corridor outside the lab so that they could be examined for contamination. The agency said it has tested 29 people for exposure, but it has not revealed exactly how many people were exposed or to what extent.
The amount of plutonium that escaped from the broken vial into the environment also still isn't clear. Estimates based on radiation measurements in the lab indicate 76 to 87% of the original sample is still in the room, but NIST's official statement says the amount is unknown. The lab where the incident took place has been closed and sealed since the spill. It will remain sealed until NIST develops a decontamination plan. NIST has not said how long that will take.
The reports highlight one incident on that day that demonstrates some of the confusion over radiation safety procedures: An unidentified person suggested that the potentially contaminated people in the corridor outside the lab remove their shoes to avoid further contamination of the area. But because the hallway was already contaminated, the result was that peoples' socks and feet became contaminated as well.
NIST reported that a "small number" of lab personnel, including the guest researcher, were internally exposed to plutonium through inhaling or ingesting some of the sample powder. NIST estimates that none of the doses exceeded 400 millirem, and most were well below 100 millirem. For comparison, NIST noted that the annual background exposure of the general public to radiation in the Boulder area is about 450 millirem, based on estimates from the National Council on Radiation Protection & Measurements. More precise testing of the lab personnel is under way, but results are not expected for a couple of weeks.
Investigations of the incident indicate that the guest researcher should not have been using the plutonium. "The source user at the time of the event had no radiation safety training, contrary to NIST program requirements," wrote Lester A. Slaback, a retired NIST health physicist and one of the experts the agency asked to investigate the incident, in his report. Slaback noted that the actual handling of the plutonium vial by the researcher "bordered on the cavalier."
NIST also asked Kenneth C. Rogers, a former commissioner at NRC, to investigate the spill. At the subcommittee hearing, he reported that although the guest researcher did not have any radiation training from NIST and was unaware of how to respond in an emergency, the principal investigator allowed him to work with the plutonium anyway. Rogers reported that the guest researcher "did not act in a prudent manner in handling the source, and because he was untrained in such matters, he was not aware of the course of action that should be taken in the event of a release to the environment of the plutonium powder."
Rogers explained his primary finding to the subcommittee as follows: "There is no uniform system, supported at all levels of management, to nurture and support a culture of safety awareness as a high priority in every NIST-Boulder activity." He added that safety at the Boulder facility has been minimally supported financially and it has had to operate with inadequate technical and human resources. These conclusions are similar to those reported by the other NIST investigators.
NRC's preliminary examinations of the situation also raised concerns about NIST's procedures. Charles L. Miller, director of the Office of Federal & State Materials & Environmental Management Programs for NRC, told the subcommittee that his office quickly dispatched people to look into the NIST spill. On the basis of their work, "NRC is concerned about a number of issues," Miller said. Among them is the amount of radioactive substance released into the environment, the severity of the individual exposures, and the proper use of procedures at Boulder, particularly those related to handling and storage of radioactive material.
Subcommittee members noted that NRC had not inspected the Boulder facility in many years, and they asked Miller why that was the case. Miller explained that the facility was considered relatively low risk, given the small amount of radioactive material the lab uses. Normally, a cursory inspection of such a low-risk facility would be done only every five years, he noted. The NRC license at the Boulder lab had been amended only a couple of years ago to include use of plutonium but only under specific conditions, Miller said. He added that NIST is required by its license to provide training to all individuals handling the material, which does not seem to have been the case.
OUTSIDE OF NIST, concern over the contamination is also growing. Because the guest researcher washed his hands in a regular sink, the material on his hands entered the local wastewater system. NIST said it is coordinating with the City of Boulder Water Quality & Environmental Services to estimate the amount of plutonium that might have been discharged into the sanitary sewer. Early calculations based on the amount of material left in the lab put the amount at less than 60 mg, which NIST reported would be below federal and state regulations for plutonium discharge into sewers.
This finding has not satisfied the City of Boulder. In a letter to the House Science & Technology Committee, Stephanie A. Grainger, interim city manager, said that the lack of containment facilities at the NIST lab and poor compliance with safety protocols are unacceptable. The city therefore has asked that a number of steps be taken to improve communications and safety for those who live around the Boulder labs.
These steps include, in part, the development of a communications plan among the city, NIST, and other jurisdictions involved in regulating materials at the labs; prompt completion of a decontamination plan for the contaminated site, which will be made public; and the preparation of a publicly available assessment of all radioactive material, chemicals, and hazardous compounds at NIST-Boulder.
Grainger also noted that the city has incurred expenses for testing and monitoring its water supplies after the incident and will incur more. She said the city should be reimbursed for this cost and indicated that NIST has signaled its intention to accommodate this request.
Turner told the subcommittee that he has asked for a meeting with city officials to discuss their concerns and how his agency can address them.
"This has shaken NIST to its core," Turner said. "I have, however, been heartened by the response from the lab directors. I also have met with representatives of the researchers and know that they are taking this situation very seriously and are committed to fixing it."
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