That spring morning, Alexander V. Kirichenko knew something was amiss.
Early Saturday, April 26, 1986, he'd gone to his basement laboratory at the Medical University of Kiev in Ukraine to turn on the gamma camera and begin the day's research. But the camera was registering high radiation levels. Thinking a colleague had contaminated it, he cleaned the detector, only to find it still registering high readings.
Asking around, Dr. Kirichenko caught wind of a rumor: Technical problems at the Chernobyl nuclear power station, 50 miles northeast of Kiev and its population of 3 million, had caused a radiation release.
And that's how Dr. Kirichenko, now a radiation oncologist at Allegheny General Hospital, learned early details about the world's worst nuclear accident.
He headed outside with a radiometer and recorded high readings. Shortly after the accident, the government announced a technical problems at Chernobyl. Fears were compounded when the Soviet Union evacuated 45,000 residents from the city of Pripyat, two miles from the power plant, within a day using buses borrowed from Kiev.
"On the radio there was nothing about it -- just classical music," Dr. Kirichenko said. "The government didn't want a panic situation."
But radiation levels in Kiev continued rising up to 100 times higher than typical background levels. Residents could smell and taste radioactive iodine in the air. Speculation swirled about a possible nuclear blast.
"People were really scared. The stress was unbelievable," Dr. Kirichenko said. It would be several days after the accident began before the Soviet government finally made an official announcement, which still downplayed its seriousness, he said.
Yuri Nikiforov, a native of Minsk, Belarus, and now director of the University of Pittsburgh School of Medicine's Division of Molecular Anatomic Pathology, was completing his medical training when the accident occurred. In time, he was summoned to Chernobyl to treat radiation victims and still has a bank of blood samples he collected that he hopes will provide important insight into how the accident affected human health.
His research on the molecular basis of thyroid cancer describes how radiation damages DNA, and why that damage causes cancer in some but not others. He said he's planning an announcement about his findings in coming months.
Both Pittsburgh physicians agree: Government secrecy about Chernobyl heightened the health impact.
Childhood thyroid cancers from exposure to radioactive iodine began showing up five years after the accident; estimates are 6,000 to 10,000 more cases than would be expected of that cancer. The Soviet government could have prevented many of those cancers by announcing the accident immediately and distributing potassium iodide pills to saturate the thyroid gland with safe iodine and protect it against the radioactive kind.
"Most [of the thyroid cancers] could have been avoided if the government had released information not to drink the milk and eat fresh greens," Dr. Nikiforov said, noting that the fallout contaminated crops, food and pastures. "It could have cut the cases by more than half."
He said 80 percent of the thyroid cancers occurred in children living at the time within 50 miles of Chernobyl, with the remaining 20 percent occurring in children living within 200 miles of the damaged Reactor No. 4. Remaining questions are whether strontium and cesium, radioactive elements with long half lives released during the accident, will cause excess lung, bone and other cancers in coming years. Cases of leukemia, high in Japan after two atomic-bomb blasts, are not elevated in Ukraine, but doctors continue watching for signs of additional problems.
The worst cases of radiation sickness during the accident were treated in Moscow, but Dr. Kirichenko said he treated emergency rescue workers in Kiev with symptoms of serious radiation sickness, including fatigue.
The Chernobyl accident released 50 million "curies," a measurement of radioactivity, within the first week of the accident, equivalent to what dozens of Hiroshima atomic bombs would produce, Dr. Kirichenko said. About 30 percent of that radiation release was in the form of radioactive iodine. However, Chernobyl proved less deadly due to the types of radiation exposure and manner of radioactivity release, he said.
Radioactive iodine, with a half life of only eight days, decays rapidly, so quick preventive action to limit exposure is important.
Dr. Kirichenko, his son Vladimir, and colleague Ernest D. Werts, also of Allegheny General Hospital, are seeking to publish a review study that describes the concentration and spread of Chernobyl's radiation contamination, its environmental and health impacts, and results of countermeasures. The study notes that children and pregnant women were most prone to radiation health damage.
"I think we learned a lot, but we should learn more -- how to manage a disaster of this scale, how to manage contaminated land, ways that the contaminated land can be reused and the long-term health effects of the low-dose irradiation," Dr. Kirichenko said.
Chernobyl also can teach preparedness for nuclear accidents. Such accidents and events differ widely but provide rare chances to turn potential disasters into educational opportunities.
Chernobyl, Dr. Kirichenko said, "changed our lives completely."