Hanford Challenge is calling for an independent study of the threat that radioactive contamination might pose to the Tri-Cities from the Hanford nuclear reservation.
On Tuesday it released a research report by Marco Kaltofen, an engineer with Boston Chemical Data Corp., who has been collecting Hanford-area samples at times since at least 2008.
His latest report found “modest but detectable level(s)” of radioactive material that had collected on the air filters of three vehicles belonging to Hanford workers.
The vehicles had been checked and cleared to leave the Hanford nuclear reservation, where they had been at the Plutonium Finishing Plant.
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Most of the remaining work to demolish the plant has been on hold since December when a spread of radioactive contamination was detected after most of the demolition of the plant’s most contaminated unit, the Plutonium Reclamation Facility, had been completed.
Checks of workers found 42 workers had inhaled or ingested radioactive particles in the December incident or an earlier contamination spread at the plant in June.
Very low levels of radioactive contamination were detected in air samples collected several miles away from the plant.
After the December incident, radioactive contamination was found on government and worker cars and truck, some of which were driven off site.
Hanford officials found seven personal vehicles that were contaminated. They were released to workers after decontamination.
Hanford Challenge took the checks a step further.
It collected the filters from 29 private vehicles driven by Hanford workers that had cleared to leave the nuclear reservation, according to the report. He also collected dust samples from wiping off an additional car.
Kaltofen removed the dust from the filters and sent samples of the dust to a licensed radiological testing laboratory for analysis.
The laboratory detected americium, uranium and thorium in multiple dust samples, he said.
“For at least three of the 30 tested personal vehicles, there remains residual alpha-radiation contamination despite being cleaned and released for use by the Department of Energy,” he said.
Given the limited number of vehicles checked in the study “it is assumed the full potential for radioactive particulate matter in these released vehicles has not been explored,” the study said.
Tom Carpenter, executive director of the Seattle-based watchdog group Hanford Challenge, said the finding point to “an urgent need for a deeper, broader look by an independent entity.”
The Washington State Department of Health had not evaluated the findings released Tuesday afternoon, but said in February that it would not be entirely surprising to find some contamination in vehicle air filters, given that the Department of Health has found contamination in the air at Hanford where the vehicles were driven.
The Department of Energy did not comment on Kaltofen’s report Tuesday.