New hazardous chemical turns up in tanks

Wednesday, September 22, 2004

By SHANNON DININNY
THE ASSOCIATED PRESS

Traces of a potentially deadly chemical have been detected for the first time in samples from underground waste tanks at the Hanford Nuclear Reservation, and a citizens watchdog group has raised concerns about worker safety.

The chemical, dimethyl mercury, can be inhaled, ingested or absorbed through the skin. Depending on the amount and type of exposure, the substance can irritate the eyes, skin and lungs, or result in damage to the central nervous system or even death.

Dimethyl mercury had never been detected near Hanford's 177 underground tanks because no one had looked for it. The tanks hold 53 million gallons of radioactive liquid, sludge and salt cake from decades of nuclear weapons production during World War II and the Cold War.

The contractor handling the tank waste cleanup, CH2M Hill Hanford Group, began sampling for the substance for the first time this summer after it was detected at the Savannah River nuclear site in South Carolina.

The sampling was conducted at a group of 12 tanks known as C-Farm. Those tanks were targeted because their basic mercury levels posed the greatest potential among Hanford's tanks to produce dimethyl mercury, said Joy Turner, a CH2M Hill spokeswoman.

Fourteen samples were taken, from tank contents, the air cavity inside the tanks and from aboveground tank filters. Results are known on four samples, which showed "barely detectable levels" of dimethyl mercury that are not threatening to human health, Turner said.

She could not say precisely what part of the tanks the four samples came from.

The results of the remaining samples were not yet available.

Turner stressed that only workers gathering the samples have been allowed in the tank farm and only with protective gear to ensure dimethyl mercury poses no threat to them.

Officials with the Government Accountability Project, a citizens watchdog group that released the test results to the public yesterday, countered that the presence of dimethyl mercury at any level poses a threat to workers.

"This chemical is so rare and unusual, we're concerned they found any, and it was found at a time when no work was being done in the tank farm," said Tom Carpenter, director of GAP's nuclear oversight campaign. "This is lethal at very low levels."

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