Upon discovery of the contamination incident by a Laboratory employee on Monday, health physics and nuclear response experts were sent to the employee's house as part of the Department of Energy's Radiological Assistance Program (RAP) team to survey the employee's car and residence. The survey detected trace amounts of americium 241 in the car and in several locations inside the employee's home.
Americium 241 is a man-made metal produced when plutonium atoms absorb neutrons in a nuclear reaction. The largest and most widespread use of americium-241 is as a component in household and industrial smoke detectors, where a small amount is used in an ionization chamber inside the detector.
Experts involved in the investigation have estimated that the amount carried off site is a fraction of the radioactivity contained in a typical residential smoke detector.
Officials are also examining any possibility that the contamination was more widely spread to other locations. However, the extremely low levels of radioactive material found at the employee's home do not pose a credible risk to the general public.
An investigation is underway to determine the origin of the contamination and whether established safety procedures and protocols were followed.
"Our first concern is to ensure that every employee is safe and that the general public is protected," said Laboratory Director Robert Kuckuck. "We believe that this has been accomplished."
"It is important that we establish the causes of this event and whether our institutional procedures were adequate and followed so that we can learn from this incident and take appropriate measures to prevent this from happening in the future," Kuckuck added.
The researcher has been placed on a special bioassay-sampling regimen. These are tests that reliably measure the amount of americium in a urine sample, even at very low levels. Using these measurements, scientists can estimate the total amount of americium 241 present in the body. Tests are also being conducted to determine if any americium is present in the researcher's lungs.
Five coworkers who work in the same workspace have also been placed on similar bioassay sampling regimens.
Workers in the facility where the contamination occurred were sent home Tuesday afternoon so experts could complete radiological surveys and clean up any residual contaminants in the building. Subsequent testing has confirmed that no other employees in the facility have been contaminated.
RAP is NNSA's first-responding resource in assessing such situations and advising decision-makers on what further steps could be taken to evaluate and minimize the hazards off site. Specific areas of expertise include assessment, area monitoring, and air sampling, exposure and contamination control.
RAP is capable of providing assistance in all types of radiological incidents. Requests for assistance may relate to facility or transportation accidents involving radiation or radioactive material. RAP's support ranges from giving technical information or advice over the telephone to sending highly trained people and state-of-the-art equipment to the accident site to help identify and minimize any radiological hazards.
Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and Washington Group International for the Department of Energy's National Nuclear Security Administration.
Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.