This Date in UCSF History: Nuclear Plants a Health Menace?

Originally published in Synapse on January 11, 1980. Anti-nuclear activists Dr. Helen Caldicott and Dr. John Goffman are “biased” charged UCSF radiology professor Dr. Harvey M. Patt.

Caldicott and Goffman, said Patt, have become “emotionally involved” in the nuclear power issue and have thus sacrificed their scientific objectivity.

“It is not my intention to take a position, but merely to tell you what I think,” said Patt in his recent UCSF “Brown Bag” lecture on the problem of low-level radiation from nuclear power plants.

In his lecture and a subsequent Synapse interview, the director of the UCSF Radiobiology Laboratory expressed the point of view that radiation exposures from nuclear power plant operation or accidents such as Three Mile Island are minimal, especially when compared to the amount of natural background radiation that all are exposed to.

Though Patt admitted that there is no “threshold” for radiation effects — that any radiation exposure can, in fact, cause cancer or mutations — he emphasized that the possible ill effects from exposure to radiation from nuclear power plants must be “put in perspective.”

That is, they must be weighed against the need for energy production, and risks presented by other modes of energy production and other aspects of modern life. Perception of priorities

“In a way the old adage that what we don’t know won’t hurt us applies to our perceptions of priorities,” said Patt.

He said that the public may be overly concerned about radiation dangers because we know “much, much more” about radiation that about other environmental health threats such as industrial or agricultural chemicals.

In addition, said Patt, the devastation and horror caused by the atomic bombings of Hiroshima and Nagasaki may have unduly prejudiced the American public against nonmilitary nuclear power uses.

The public concern over nuclear power, however, may be exacerbated by the fact that, according to Patt, though we are now all too familiar with the effects of high doses of radiation, “we just don’t know” much about the human biological effects of low-level radiation.

And while the most dramatic risk of nuclear power may be the possibility of a full-fledged “melt-down” sometime in the future, the most immediate, pervasive risk is the harm that low-level radiation may already be imposing on nuclear workers and those in the population exposed to “minor” accidents such as the one at Three Mile Island.

In recent years some epidemiological studies have shown a significantly increased incidence in cancer among groups of nuclear power workers exposed to low levels of radiation.

In 1978, for example, after studying the death certificates of 3,710 workers at the Hanford, Washington atomic reactor, Dr. Thomas Mancuso reported a six to seven per cent increase in radiation-related cancer deaths among Hanford workers.


According to Patt, however, Mancuso’s results and those of similar studies have been declared invalid by some members of the scientific community who deem the methodology imperfect. Based on these criticisms Patt has rejected the conclusions of the existing epidemiological studies on human effects of low level radiation.

According to Patt, if one accepts Mancuso’s estimation of the powerful effects of low doses of radiation, one must be led to the conclusion that about half of the current cancers in the United States are caused by the pervasive natural background radiation.

The natural background radiation, caused by cosmic rays, natural radioactive substances in the ground, and radioactive substances in the body, exposes Americans to an average of 100 millirems of radiation a year.

The dose of natural background radiation varies widely, however, from place to place so that while San Franciscans are exposed to about 40 millirems a year, residents of Leadville, Colorado, who live at a higher altitude, are exposed to about 125 millirems a year.

Causes According to Patt, however, of the 360,000 cancer deaths per year in the United States only 3,500 are caused by natural background radiation and another 3,500 by “manmade” radiation sources such as medical x-rays, television sets, smoke detectors, nuclear power plants, and fallout from nuclear weapons tests.

If low level radiations were as powerful as Mancuso’s results suggest, Patt says, he would expect to find not only more cancers caused by background radiation, but a demonstratable increase in cancers in those areas with higher natural background radiation.

And this is not the case, says Patt. In addition to rejecting the epidemiological studies on human effects of low level radiation, Patt also refuses to apply the results of animal tests with low level radiation to humans.

According to Patt, the only “conservative and reasonable” way to assess the effects of low level radiation on humans is to make a linear extrapolation from what is already known about high level radiation effects.

In his lecture Patt used such a linear extrapolation to estimate the effects of the Three Mile Island accident.

According to Patt, the Three Mile Island accident exposed the surrounding population of two million people to an additional radiation burden of only one per cent of the existing natural background radiation.


By way of comparison, Patt noted that one medical x-ray exposes a patient to a radiation dose equal to 90 per cent of natural background while one ride in a jet airplane exposes an individual to a dose “equivalent to or perhaps greater than that received by the individuals living around Three Mile Island.”

“It would be manifestly impossible to detect a significant effect at this level of radiation on the population at Three Mile Island,” said Patt.

However, he added that “if we exaggerate the dose (imposed by the Three Mile Island accident) to equal the natural background dose for one year, based on the linear extrapolation ... it would cause some 20 to 40 cancer deaths above the expected lifetime experience for this population...which is 320,000 cancer deaths.”

“No cancer death is insignificant” said Patt, “But I say let’s put this into perspective with the 300 people killed in automobile deaths on a three day holiday weekend...or the numbers of people dying from various occupational hazards.”

Using this “perspective” Patt asserts that “there have been far fewer deaths resulting from nuclear energy in a peacetime setting than from most other energy sources.”

By way of example, Patt points to the appalling number of workers who have died mining coal.

The problem with this argument, however, is that while the cancer latency period may be from 10 to 40 years, nuclear power plants have only been around 25 years.

Even Patt admits to the difficulty of uncovering nuclear power related deaths or identifying “deaths-in progress” due to nuclear power radiation exposure.

Plants Though

Patt seemed to spend most of his lecture minimizing the dangers of nuclear power plants, he concluded his talk by confessing that he would not like to live next to a nuclear power plant.

And he does, in fact, worry about the problem of nuclear wastes which may remain radioactive for thousands of years and for which a fool proof method of containment has yet to be found.

Nevertheless, Patt added that his first concern might be allayed by centralizing nuclear power plants in remote areas. As for the problem of nuclear waste, for which no solution has been found after 25 years of effort, Patt was content to trust to future technology.

“I do not know whether the problem (of nuclear waste disposal) is solvable, but I like to think that it is,” said Patt.

Patt’s optimism about nuclear power seemed to be based on his pessimism about the nation’s ability to meet its energy needs either through other “safer” technologies or through conservation.

‘Not selling reactors’

“I’m chairman of the campus conservation committee,” Patt pointed out. “So I’m not selling reactors, I’m selling conservation... But I’m not sure how far we are willing to go with this conservationist mode and how willing we are to give up certain aspects of our lifestyle to accommodate it. And we are going to need energy and more of it and other sources of energy may turn out to be equally hazardous or more 50...”

Throughout his lecture Patt implied that insistent needs for “energy and more of it” necessitate keeping the possible benefits of nuclear power in mind at all times when assessing the possible “risks” of nuclear radiation.

Anti-nuclear activists charge, however, that economic and other factors have effectively reduced the “benefits” side of the nuclear power equation.

Among these factors they cite the fast approaching exhaustion of uranium supplies, uranium’s skyrocketing cost, and the increasing costs of uranium processing and nuclear plant construction.

Why risk even a small number of radiation caused cancers, argue these activists, to perpetuate still another energy modality dependent on an increasingly expensive, nonrenewable energy source?

Patt said he had no answer to this argument. Though he may be considered an expert in radiation effects, Patt said he knew very little about the economics of nuclear power.

The completed but not yet licensed Diablo Canyon nuclear power plant in San Luis Obispo. A UCSF professor says that radiation exposure from plants is minimal compared to the amount of exposure to natural background radiation.