HILO — The federal Nuclear Regulatory Commission is reviewing a proposed radiation monitoring plan for Pohakuloa Training Area.
HILO — The federal Nuclear Regulatory Commission is reviewing a proposed radiation monitoring plan for Pohakuloa Training Area.
The U.S. Army is required to develop the plan as a result of use of depleted uranium — a dense, weakly radioactive metal alloy — in spotting rounds fired in the 1960s.
Sampling would occur quarterly in an intermittent stream north-northwest of the training area.
The location, downstream of the firing ranges, was selected based on an analysis of potential migration pathways for depleted uranium outside the training area, according to the plan.
The 131,425-acre training area is located off Saddle Road between Mauna Loa and Mauna Kea.
Maureen Conley, NRC spokeswoman, said in an email the commission might make a decision by the end of January. If approved, the Army would be required to implement the plan within six months.
The NRC issued the Army a license for depleted uranium possession in 2013 after its past use was discovered at PTA and other facilities. The plan is a requirement of that license.
The spotting rounds contained 6.7 ounces of depleted uranium, according to the Army. They emitted white smoke on impact but did not explode.
Since it’s not known if the rounds were cleaned up, the Army says it’s assumed that “most, if not all, of the 140 kilograms” of depleted uranium fired at PTA and Schofield Barracks on Oahu remain within the radiation control areas, where they were fired.
The spotting rounds were part of the Davy Crockett weapons program from 1960 to 1968.
The document says a “source-pathway-receptor interaction” at the Davy Crockett ranges was “considered unlikely.” It cites the “low mobility” of metals in soil and the depth of groundwater, located more than 1,000 feet below the training area.
“Despite occasional flow, water in the intermittent stream channels infiltrates rapidly once precipitation stops and the streams become dry,” the plan says.
Jim Albertini, an outspoken critic of PTA, said more needs to be done.
“The PTA radiation monitoring plan is totally inadequate,” he said in an email. “What is needed is comprehensive, independent testing and monitoring that has the confidence of the community.”
Michael Reimer, a retired geologist in Kona, also said the plan falls short.
“Claiming that uranium is such a heavy element it cannot migrate far from its source is absolute nonsense,” he said in an email to the NRC.
Lt. Col. Christopher Marquez, PTA commander, said in an email to the Tribune-Herald that the sampling site was chosen based on the possibility of sediment being carried out of the depleted uranium area.
“The NRC is considering our proposal and could require us to move it, to add more locations, or both,” he said.
Marquez said air sampling is not required for the license.
“As one example of the Army’s position on air sampling, if the DU were aerosolized and carried in the air away from the DU area at only a tenth of the NRC’s permissible limit on a continuous basis, all 140 kilograms of DU used in Hawaii would have been displaced long ago,” he said. “The Army presented the data supporting this to the NRC, which agreed with the conclusion.”
The state Department of Health has said that the Army’s previous use of depleted uranium, which has 40 percent the radioactivity as naturally-occurring uranium, is not considered a “significant health threat.”
Air sampling taken near Waikoloa Village in 2009 found normal background levels of natural uranium and no detectable depleted uranium, the department said.
Email Tom Callis at tcallis@hawaiitribune-herald.com.