Although radiation from the Chernobyl nuclear power-plant accident could have disastrous health consequences for persons living in the Kiev region, U.S. experts said yesterday that airborne particles carried elsewhere are expected to have minimal global impact.
Authorities said, however, that other countries have recorded above-normal radiation readings.
While initial levels reported in Sweden did not appear to pose immediate or long-term health hazards there, authorities in Poland were reportedly taking precautions to protect against possible fallout, particularly of radioactive iodine.
John Kasper, a spokesman for the Environmental Protection Agency, designated head of a coordinated U.S. response to the disaster, said yesterday that the EPA will increase daily radiation monitoring at 67 sites, including at least one in each state.
Kasper said the most recent National Oceanic and Atmospheric Administration (NOAA) data suggest that winds carrying the contaminated air mass have shifted since the accident last weekend.
While initial movement was to the northwest into northern Europe, it is expected to move in the next few days east or southeast, back above the northwestern Soviet Union, he said.
"During the next few days, it is expected the air mass will be dispersed by atmospheric activity, but it is too early to determine whether any portion will reach the U.S. . . . . The important thing to remember is that it won't pose a significant risk," he said.
Given the paucity of information from the Soviets about the accident, U.S. officials and other experts cautioned that potential health consequences will not be understood for some time.
Yesterday, most scrambled to decipher meager bits of information from media reports and from colleagues in Sweden, first to report the magnitude of the disaster. They noted the expected danger of short-term radiation poisoning, which can cause illness and death, and of increased long-term prospects of cancer.
"It's quite possible there will be detectable amounts of radiation reaching the U.S. There definitely will not be a hazard here . . . . I don't think there will be health consequences beyond Russia," said Dr. Henry Wagner, director of nuclear medicine and radiation health at Johns Hopkins Medical Institutions.
"From what I've heard of the Swedish dose rate, it is innocuous," said Dr. James Potchen, chairman of the radiology department at Michigan State University and former president of the Society of Nuclear Medicine. "It's not dissimilar to two chest X-rays" over a year.
Dr. Eugene L. Saenger, a well-known radiology professor at the University of Cincinnati, said that reports from Sweden, hundreds of miles from the accident site, suggested "trivial biological effects" and that the potential in this country would be even less so.
"I don't think we have any previous experience on this order of magnitude" for a nuclear accident, he added, noting that the difference between the Soviet accident and the one at Three Mile Island near Harrisburg, Pa., in 1979 is the "difference between heaven and hell."
Although the TMI accident was the worst in U.S. history, no significant amount of radiation was released, he noted.
John Villforth, head of the Food and Drug Administration's Center for Devices and Radiological Health, recalled yesterday that government estimates after TMI projected that only one additional fatal cancer might be expected over the lifetime of the 2 million persons living around the plant, compared with 325,000 fatal cancer cases normally expected.
There is no confirmed information about the amount of radiation spewing from the Chernobyl plant. If high doses were released, as is suspected, workers and individuals nearby could face severe radiation sickness and death. Potchen said acute symptoms include diarrhea, followed by anemia and loss of resistance to infection.
Dangerous radioactive isotopes can also contaminate water and food, particularly milk and vegetables, posing short and long-term hazards.
Major concerns in contaminated food are radioactive iodine, which can concentrate in the thyroid gland and lead to loss of function and thyroid cancer, and radioactive strontium and cesium that can lodge in tissues throughout the body and increase risk of cancers such as leukemia.
Many of the most dangerous radioisotopes are likely to contaminate nearby areas, but Villforth said it is difficult to predict how much would be carried high enough into the atmosphere to be transported worldwide. Radioactive gases, such as xenon and krypton, can be carried most easily but are generally inert and not biologically dangerous.
A drug can be administered to block accumulation of radioactive iodine. The Los Angeles Times reported from Warsaw that Polish authorities planned to administer this as a preventive measure because radioactive iodine had been detected.
Washington Post correspondent Karen DeYoung reported from Stockholm that such precautions were not recommended there but that radioactive iodine and cesium were among about 18 radioactive isotopes measured there. Officials there noted that most are short-lived and break down quickly.
Swedish estimates, DeYoung reported, suggested that the average Swede will be exposed to radiation only about 2 to 3 times more than the normal yearly dose.