Study finds normal rate of cancer near Hanford

KENNEWICK – Living near the Hanford Nuclear Reservation does not appear to increase cancer rates, according to a study published in the journal Health Physics.

The study looked at the number of cancer deaths in Benton, Franklin, Adams and Walla Walla counties from 1950 through 2000.

The findings were consistent with an earlier study that looked at cancer death rates near Hanford from 1950 through 1984, said epidemiologist John Boice, who worked on both studies.

The earlier study was conducted by the National Cancer Institute, using taxpayer money. DuPont, an early Hanford contractor, paid for the more recent study that looked at cancer rates over 16 more years.

DuPont is one of the contractors being sued in federal court in Spokane by people who believe radiation released from Hanford caused their thyroid cancer. Boice has testified for the defendants in the case.

Between 1944 and 1957, radioactive particles were released into the air from Hanford factories processing irradiated uranium to produce plutonium for the nation’s nuclear weapons program. The particles were blown downwind of the Hanford site.

The study compared cancer rates in the four counties near Hanford, where radiation exposure is believed to have been the greatest, to five other counties not downwind of Hanford. The Washington counties of Douglas, Skagit, Chelan, Kittitas and Whatcom were selected as a control group because they had similar economic and social characteristics.

The only statistically significant difference in cancer rates between the Hanford counties and the control counties was a lower rate of lung cancer deaths for those near Hanford, Boice said.

That may be because people near Hanford were less likely to smoke cigarettes, the study said.

The study did find a higher death rate than expected for prostate, brain and childhood cancers, but found the same increase in Hanford counties and the control counties.

Thyroid cancer was of particular interest because the most common radioactive isotope in the airborne releases was iodine 131. The iodine drifted downwind to settle on crops and pastures where dairy cows grazed. When milk and produce contaminated with iodine 131 are consumed, the radiation concentrates in the human thyroid.

The study found 33 thyroid cancer deaths in the Hanford counties compared with 76 deaths in the control counties, which had a larger population. The thyroid cancer death rates, which consider the differences in population, were similar.

However, the study noted that mortality information is not the best way to check for thyroid cancer. Improved therapy has lowered death rates in recent years, and thyroid cancer deaths were relatively rare, the study said.

But the number of deaths was large enough to provide information on the possible level of risk, Boice said.

The same study methods were used for both the National Cancer Institute study and the more recent study, Boice said. The only difference is some change in the counties studied.

The results of the recently published study are consistent with the U.S. Centers for Disease Control and Prevention’s Hanford Thyroid Disease Study, completed in 2002 at a cost of $22 million. That study did not find increased thyroid cancer rates in people who lived downwind of Hanford as children.