WIPP Workers' Radiation Exposure Confirmed
Thirteen employees of DOE's Waste Isolation Pilot Plant near Carlsbad, N.M., were notified Feb. 26 that they have tested positive for radiological contamination after being exposed on Feb. 14.
Thirteen employees of DOE's Waste Isolation Pilot Plant near Carlsbad, N.M., were notified Feb. 26 that they have tested positive for radiological contamination after being exposed on Feb. 14. Jose R. Franco, manager of the U.S. Department of Energy's Carlsbad Field Office, said in a letter addressed to local residents that the employees "were notified within about 12 hours of the receipt of preliminary sample results."
Since the workers were exposed, only essential personnel have been allowed access to the site, and shipments to it have halted, the Associated Press' Jeri Clausing reported. The Carlsbad Environmental Monitoring and Research Center, which is operated by New Mexico State University, is conducting environmental monitoring and testing on and around the site.
"The material for this release event is transuranic radionuclides," Franco wrote. "The release material was predominantly americium-241, material which is consistent with the waste disposed of at the WIPP. This is a radionuclide used in consumer smoke detectors and a contaminant in nuclear weapons manufacturing. Determining employee dose typically involves multiple sample analyses to determine employee's radionuclide excretion rate over time. This allows the lab to estimate the employee’s accumulated internal dose. The time this process takes depends largely on the solubility of the inhaled particulate, with less water-soluble radioactive materials requiring more samples and time to accurately estimate the dose. Follow-up urine samples may require about three or more weeks to accurately predict dose.
"We are now focusing our sampling program on employees with work assignments that may have placed them at greater risk, including those on shift February 15. We are still reviewing staff assignments to determine if additional employees will need to be tested. However, employees who feel they were assigned positions or functions that placed them at risk will be included in follow-up bioassay monitoring at their request. There is no risk to family or friends of these employees.
"At the time of the event, these employees were performing above ground operations, and federal oversight duties at the WIPP facility. Nuclear Waste Partnership, LLC, the site contractor, requested that all workers on site the night of the event submit follow-up bioassay samples as they were considered more likely to have indications of potential exposure. Additional samples will be collected from these employees in the weeks ahead in order to perform complete analyses. It is premature to speculate on the health effects of these preliminary results, or any treatment that may be needed. However, on-site sampling and surveys and environmental monitoring, to date, continue to support National Atmospheric Release Advisory Center (NARAC) modeling, which indicates that airborne contamination was likely at very low levels," he added.