A postgraduate student intern and an Oak Ridge Associated Universities researcher in Tennessee are working to replicate an infamous 1976 radiation accident at the Energy Department’s Hanford Site in Washington state.
The event exposed Harold McCluskey, a chemical worker who would become known as “The Atomic Man,” to the highest known level of the radioactive isotope americium-241 ever recorded.
Oak Ridge Associated Universities health physicist Jason Davis, working with summer intern Daniel DiMarco, intend to safely recreate the incident to measure the physiological effects of chronic low-dose radiation. They hope their findings can help them establish data to better prepare first responders and clinicians for what might happen to a patient’s body over time after radiation exposure.
“From a purely scientific perspective, we don’t know a lot about chronic low-dose radiation,” said DiMarco, who is between his undergraduate and post-graduate years at Louisiana State University. “We know much more about what happens from accidents. We need a bigger data set.”
Exposure
In August 1976, McCluskey, then 64, was working a night shift at Hanford’s Plutonium Finishing Plant, where plutonium was molded into its final form for use in nuclear weapons. He told People magazine in 1984 that he had just returned to the plant’s Americium Recovery Facility following a five-month strike.
Under his supervisor’s instruction, McCluskey used a glove box to add nitric acid to columns containing radioactive americium, though resins on the columns had been left unattended for months during the strike.
The nitric acid and resin mixed and the column exploded, showering McCluskey with acid and radioactive material and exposing him to 500 times the amount of radiation considered safe for a person to endure in one lifetime.
Local media accounts of the incident describe McCluskey, blinded and temporarily deaf from the blast, being taken to a concrete isolation area where he stayed for five months. The local Tri-City Herald newspaper reported that the Department of Energy said McCluskey’s body was so irradiated that he set off Geiger counters at a distance of 50 feet.
McCluskey endured chelating treatments to reduce the amount of radiation in his body before he was eventually able to go home. He died of a heart condition unrelated to his radiation exposure more than a decade later.
The Americium Recovery Facility would informally become known as the “McCluskey Room.” It was demolished earlier this year as part of the ongoing teardown of the Plutonium Finishing Plant.
Research
To safely replicate the incident, DiMarco and Davis designed an experiment that uses a radioactive cobalt isotope in a sealed source instead of liquid americium. Rather than risking exposure to themselves, the two donated vials of their blood to irradiate for different lengths of time.
Then, the researchers added a drug that freezes cells going through mitosis in metaphase. During metaphase, chromosomes line up before they split apart, allowing the team to see and count the centromeres to which chromosome spindles attach themselves.
Davis and DiMarco are looking for chromosomes that have two centromeres, called dicentric chromosomes, which can result from radiation exposure. Most people have a few in their body already, according to Davis: “But, when more are visible it’s an indication that you’ve seen some type of radiation exposure above background.”
The donated blood experiment does have some drawbacks, however, and Davis said he hopes eventually to perform the experiment on a living subject such as a mouse or rat to produce more accurate results.
The main difference is the way lymphocytes act in a living subject. The small white blood cells are constantly dying and repopulating. Irradiated lymphocytes in a living blood sample could die off and be replaced by new ones before scientists have time for measurement.
Davis said irradiating an animal’s body creates a disposal hazard, though, so he doesn’t expect that leg of the research to move forward anytime soon. “You’d be trying to dispose of a material that is both radioactive and a potential biohazard so it’s a mixed waste and it gets difficult there.”
For now, the team wants to continue the research with increasing doses and exposure times to establish data that can better prepare clinicians for what might happen over time to a body exposed to radiation.
“In and ideal case, like that of the Atomic Man, they administered a chelating agent that grabbed a lot of the americium (isotope) and just cleaned it out of his body,” he said. “It worked very well, but having the type of information Daniel and I are developing would give the clinicians a better idea of how much of the agent they need to administer and when and if the agent is going to impact other measurements on down the line.”
