Nuclear-Plant’s Neighbors Await Preliminary Data on Exposure Level : Northwest: The first results are due for release in April. But officials fear that residents will misinterpret the report about Hanford Nuclear Reservation’s impact on the area.

Scientists studying what the radiation exposure levels around the Hanford Nuclear Reservation were during the Cold War are trying to decide how to break the news of their preliminary findings to Northwest residents.

The initial announcement of results from the first-ever study on the question is due in April, and the task of releasing the data is fraught with dangers of misinterpretation.

“We’re walking such a fine line,” said Mary Lou Blazek, Hanford programs manager for the Oregon Energy Department in Salem and vice chairwoman of a panel of independent scientists overseeing the $15-million Energy Department multiphase study of radiation exposure from Hanford.

The Hanford Environmental Dose Reconstruction Project, conducted by the government contractor Battelle Pacific Northwest Laboratories, was launched after the public learned for the first time in 1986 of massive radiation releases from Hanford.

Blazek said the initial announcement may involve hypotheticals and stressed the information is subject to change as the study progresses.

“We may say if you were 16, and you lived in Pasco in 1944-’46, and your food intake was this, then your dose could have been this,” Blazek said.

Blazek, who chairs the communications subcommittee of the oversight panel, said scientists may also try to explain what the health consequences of a certain dose could be.

“It’s difficult because of the science involved,” she said. “It’s difficult because there are so many variables involved. You have to make so many assumptions.

“Say you have X millirems. That is equivalent to what? We can’t even agree on that in our own panel.”

The government said in 1986 that more than 500,000 curies of iodine-131 were released between 1945 and 1956 from Hanford during accidents and planned experiments. An estimated 15 to 24 curies were released during the 1979 Three Mile Island nuclear accident.

The studies under way are designed to estimate how much of the radiation people were exposed to in the 570-square-mile site along the Columbia River in south-central Washington.

Hanford, an old complex of military reactors that is now focusing on cleaning up extensive environmental contamination, helped build the first atomic bomb exploded in New Mexico, as well as the weapon that fell on Nagasaki.

Many Hanford “downwinders” claim the radiation releases have increased the cancer rate in the area.

A controversial and limited state study found cancer mortality rates near Hanford are actually lower than the national average, although the federal Centers for Disease Control is preparing to conduct its own $5-million study of cancer rates in the area.

The CDC has previously estimated that about 20,000 children may have drunk milk exposed to radioactive iodine from Hanford.

The Hanford dose reconstruction project is planned in four phases and may continue through 1993. Results from the first phase will reflect its limited scope, Blazek said.

The first phase focuses on 10 counties closest to Hanford: Washington’s Adams, Benton, Walla Walla, Franklin, Klickitat, Yakima, Kittitas and Grant and Oregon’s Umatilla and Morrow.

No decision has been made on whether future phases will expand the study east and south into more of rural Washington and Oregon and into Idaho, or north to the region’s population center around Spokane.

The study’s first phase will estimate exposure to iodine-131, although future phases could look at other isotopes.

The initial phase will examine exposure from airborne radiation from 1944 to 1947 and exposure through water from 1964 to 1966.

Indian tribes were not extensively studied in the first phase, but in later phases eight Northwest tribes are expected to participate. Scientists are interested in radiation exposure to Indians because their diets and life styles differ from other populations.

Although exposure levels have not been released, scientists have already come up with some potentially important conclusions.

Milk drinkers in the Walla Walla area may have received more radiation than people closer to Hanford because of the milk distribution system in place at the time, and scientists think the same may apply in Pendleton, Ore. The milk was contaminated because cows ate radioactive feed.

And potential radiation exposure from the Columbia River was probably low because of the huge river’s diffusion capabilities, Blazek said.

After the Energy Department declassified 19,000 pages of information about the radiation releases, Blazek said officials tried “sort of back of the envelope calculations” of potential radiation doses to people.

“Now we’re at an 8-by-11 sheet of paper. We’re nowhere near the finished report,” she said.