Three Mile Island Cancer "Extremely High"

The original study, performed by Columbia University, is often cited as evidence that the TMI accident near Harrisburg, Penn. caused no ill effects to the people exposed to the radiation.

But Steve Wing, Associate Professor of Epidemiology at University of North Carolina at Chapel Hill, has conducted a reevaluation of the Columbia University study, and published his results in the January 1997 issue of Environmental Health Perspectives.

Using better analytic and statistical techniques, he found that among the 20,000 people who lived near the plant and close to the plume's path, lung cancer and leukemia rates were two or more times higher than what they were near the plant but upwind from the plume. Among those in the most direct path of the plumes, lung cancer incidence went up by 300 to 400 percent, and leukemia rates were up by 600 to 700 percent.

"Several hundred people at the time of the accident reported nausea, vomiting, hair loss and skin rashes, and a number said their pets died or had symptoms of radiation exposure," he said. "We figured that if that were possible, we ought to look at it again. After adjusting for pre-accident cancer incidence, we found a striking increase in cancers downwind from Three Mile Island."

The scientists do not believe smoking and social and economic factors were responsible for the increased cancers found in the downwind sectors.

Many earlier researchers, as well as government and industry officials, accept as fact that only small amounts of radiation were released into the atmosphere, Wing said. But it is known that some plant radiation monitors went off scale when the accident started. Plumes containing higher radiation could have passed undetected, he said, because not all monitoring equipment was in place at the plant.

A TMI Public Health Fund then was established to fund research into radiation heath effects and radiation protection, hiring investigators from Columbia University to see if "risks from specified cancers may have been raised by exposure to radiation emanating from the Three Mile Island Nuclear power plant."

Cancer cases for the years for the years 1975-1985 were studied, with the Columbia team concluding that any increases were not caused from the radioactivity released at the plant.

Wing has quarreled with an assumption regarding the dosage of radiation the populate sustained. "The TMI Public Health Fund was governed by a court order which limited the scope of the health study by 1) prohibiting upper limit or worst case estimates of radioactive releases to the population, and 2) requiring that nuclear industry insurers concur on the nature and scope of the dosimetry projects."

The lawsuit, filed by 2,000 plaintiffs against the utility, was later dismissed when the court found they couldn't prove their claims.

Wing said he found it ironic that U.S. District Court Judge Sylvia Rambo, admistrator of the Fund, dismissed those thousands of damage claims filed against the power plant by nearby residents last year citing a "paucity of proof" to support their cases.

"Judge Rambo spent a year or more throwing out scientific evidence presented by the plaintiffs," he said. "After she threw out the evidence that people had been injured by the accident, including part of our work, then she ruled that there wasn't enough to proceed with the case."

He also noted that the court gave attorneys for the nuclear industry the right to review the earlier health effects research before it was made public. "I think our findings show there ought to be a more serious investigation of what happened after the Three Mile Island accident," Wing said.

Limitations of the new study, like the earlier work, include the continuing difficulty of determining precise wind direction for several days following the accident.

Researchers studied leukemias, childhood cancers, non-Hodgkin's lymphoma and Hodgkin's disease. "But their analyses of childhood cancers failed to consider birth cohorts. Therefore the Columbia analyses counted among the exposed many children who were not conceived at the time of the accident, diluting the exposed group," according to an analysis of Wing's research by the Nuclear Information & Resource Service.

But missing and inoperable equipment meant little information about the early radiation release was available. Thus the study didn't take into account the possibility that concentrated packets of radioisotopes hit certain populations.

"If the premise that maximum doses were no higher than average annual background levels is not open to question, then no positive association could be interpreted as evidence in support of the hypothesis that radiation from the accident led to increased cancer rates," Wing said.

In 1994-95, cytogenetic analyses, or cell studies, of individuals near TMI who experienced vomiting, erythema, diarrhea and other symptoms of radiation poisoning at the time of the accident showed genetic damage equivalent with levels of exposure substantially more than the maximum dose used in the Columbia study.

Wing and his colleagues found dose-response relationships between radiation exposure and cancer incidence. The data show that the higher the radiation exposure, the higher the incidence of cancer.

According to the Nuclear Service, Wing divided a 10- mile study area into 69 tracts, "each assigned radiation dose estimates based on monitor readings and atmospheric dispersion models.

"Using various models, Wing et al. adjusted for age, sex, socioeconomic characteristics, preaccident variation in cancer incidence and the medical detection bias so that these factors would not interfere with a true result.

"The routine releases from TMI unit one and their effects on the population were also accounted for by adjustment for baseline cancer rates before the accident," the Nuclear Service said.

"I would be the first to say that our study doesn't prove by itself that there were high-level radiation exposures, but it is part of a body of evidence that is consistent with high exposures," Wing said. "The cancer findings, along with studies of animals, plants and chromosomal damage in Three Mile Island area residents, all point to much higher radiation levels than were previously reported. If you say that there was no high radiation, then you are left with higher cancer rates downwind of the plume that are otherwise unexplainable."