Last week, I discussed events resulting in the Chernobyl NPF accident, including unique aspects of the reactor-design which contributed to the accident, and which resulted in release of radiation to the environment. I also discussed the initial Soviet response. Next, I focus on the immediate medical consequences and the response of Soviet government to medical interventions.
Several considerations arose immediately after the accident, including whether to evacuate people living in Pripyat, a purpose-built city (atomic city) only four kilometers from the NPF and how to deal with injured emergency response personnel. Readers may wonder why there was a city of almost 50,000 people near a NPF.
The answer lies in the poor infrastructure of the Soviet Union. In the U.S. and Europe, there is no need to build a city near a NPF, because it is easy and efficient to transport workers and materials to the site over considerable distances. This was not so in the Soviet Union, such that planners built a new city near each of nine NPFs where workers could live and materials needed for plant repairs could be fabricated.
Back to the accident: When there is an accident exposing the public to radiation, experts must struggle with the decision to evacuate people or have them shelter-in-place (stay indoors, close windows, etc.). There is a trade-off between these strategies. Evacuation can expose people to a radioactive plume with little or no shielding. Sheltering-in-place provides shielding (better in a concrete building, less so in a wooden house), but this strategy may be inadequate if ambient radiation levels remain high for a prolonged interval.
There are international guidelines, albeit arbitrary, when to shelter-in-place vs. when to evacuate based on these considerations. When it became apparent that persons remaining in Pripyat would receive too high a radiation dose sheltering-in-place, they were immediately evacuated, in accord with international recommendations.
It is worth noting the original plan was to build the Chernobyl NPF about 25 km from Kiev (population about 2.5 million). Fortunately, this proposal was vetoed by the Ukraine Academy of Sciences for safety reasons. Otherwise, we could have been considering the possible scenario of evacuating the third largest Soviet city.
As an aside, I later brought my family to Kiev to reassure people there was no need to evacuate.
Another issue (misunderstood in the HBO miniseries) is why a 30 km evacuation zone, rather than a larger zone, was chosen. Evacuation requires immediate military intervention. Soldiers need instructions—where to evacuate, who to evacuate, where to send evacuees, establish checkpoints, physical boundaries, etc.
There is no time for nuance, such as measuring radiation levels in specific towns and villages and evacuating some but not other areas. Thirty kilometers was a reasonable radius for the initial evacuation to ensure the immediate dose to any member of the public, especially susceptible populations, like children, does not exceed international guidelines.
My Soviet colleagues had considerable experience and expertise dealing with radiation victims, perhaps more than us. What they lacked were modern technologies and drugs.
HBO’s writers seem to have confused this concept with later evacuation zones in Ukraine, Russia, and Belarus, where the concern was not immediate, but cumulative radiation exposures as a result of living with environmental contamination (ground, food, water), especially from cesium-137 deposited several days after the accident when it rained as the radioactive plume passed.
We faced similar complex decisions after the Fukushima-Diaiichi NPF accident, where the 10 km evacuation zone was later extended to 30 km. A detailed discussion of the trade-off between evacuating people to prevent future cancers vs. the potential loss of life from collateral effects, such as disruption of medical care, is beyond the scope of this editorial.
Briefly, exposing 100,000 people to 100 millisieverts of radiation (10,000 chest X-rays) will cause 1,100 extra cancer deaths, whereas evacuating them will result in about extra 5,000 deaths from disruption. Not a good trade-off.
Ironically, the Shoreham NPF on Long Island, which cost $6 billion, was never allowed to operate, because it was feared the surrounding area could not be evacuated. The triumph of politics over reason and science?
Next, there is the issue of giving people iodine tablets to prevent them inhaling radioactive iodine (predominately 131-iodine) from the radioactive plume, incorporating these to their thyroid and causing thyroid abnormalities, including thyroid cancer (more on this later). The Young Pioneers were relatively successful at distributing iodine to the Pripyat residents before the evacuation. However, it was not possible to do so for people in the rural areas immediately surrounding the Chernobyl NPF.
Unfortunately, these areas of Ukraine, Russia, and Belarus has endemic iodine deficiency, such that peoples’ thyroids are iodine-avid. Compounding the problem was our inability to quarantine food in these rural areas. As I will discuss later, the major cause of thyroid cancer was children ingesting 131-iodine contaminated milk.
In the HBO miniseries, two physicists in Minsk dramatically gulp down iodine tablets. This is not a bad idea, but hardly needed. Iodine tablets are now distributed to persons living near U.S. NPFs. However, children, not adults, are the major at-risk population. We did not find any cases of thyroid cancer in persons older than about 16 years exposed to 131-iodine from Chernobyl.
Chernobyl was a storm—endemic iodine deficiency, patchy distribution of iodine tablets, and inability to quarantine dairy products (cows eat 131-contaminated grass, children drink lots of milk).
Contrast this with the Fukushima NPF accident, where we quarantined milk. Readers may be interested to know radioactive milk held for 80 days turns into non-radioactive cheese (10 eight-day half-lives of 131-iodine). Selling the cheese to people is an entirely different matter.
What about the emergency personnel?
When I arrived in Moscow, several hundred radiation-exposed persons, including NPF operators, firefighters, and other first responders had been or were being flown to Hospital 6.
Why Hospital 6 in Moscow, and not hospitals in Kiev?
When the U.S. and the Soviet Union were building nuclear weapons during the Cold War, there were many accidents exposing workers to radiation. The U.S. developed a radiation emergency response center at Oak Ridge, TN. Similarly, the Soviets established their center at Hospital 6 on the outskirts of Moscow, attached to the All Union Institute of Physics. Consequently, my Soviet colleagues had considerable experience and expertise dealing with radiation victims, perhaps more than us. What they lacked were modern technologies and drugs.
My main Soviet colleagues were Alexander Baranov, Angelina Guskova, Andrei Vorobiev, and Leonid Ilyin. As a young physician, Guskova had worked with Igor Kurchatov, the father of the Soviet A-bomb (their J. Robert Oppenheimer). Using a combination of physical, biological, and computational techniques, we identified 204 persons with acute radiation syndrome (exposed to >2 sieverts) on whom we focused our medical efforts, which we described in detail in articles in the NEJM1 and elsewhere.
Briefly, everyone received supportive care and many received antibiotics (because of low granulocytes) and antiviral drugs (radiation activates latent DNA-viruses). Some received RBC and platelet transfusions. A few received bone marrow transplants. One interesting intervention, suggested by David Golde (UCLA), was the use of a molecularly cloned hematopoietic growth factor (granulocyte/macrophage colony stimulating factor [GM-CSF; sargramostim]).
Sargramostim had been tested in dogs and monkeys to increase granulocytes, but had not been given to humans. We brought it into the Soviet Union from Switzerland—hidden in a passenger’s checked luggage with the permission of a Politburo Chernobyl commission.
The problem was, the Soviets didn’t want the Chernobyl victims to be the first humans to receive a new therapy. The solution was for Vorobiev and I to inject one another with sargramostim.
We lived, and so, we got permission to proceed.
It is important to understand that in accident settings like Chernobyl or detonation of an improvised nuclear device, there are compound injuries not just from radiation, but also from fire, percussive force and projectiles. Not only do these synchronous injuries make people more susceptible to radiation damage, they can kill people even if you successfully reverse the radiation-induced damage.
Our scorecard treating the 204 victims was reasonably good. Sadly, 29 died but we could rescue 175 (86%). If we include the two immediate deaths at the Chernobyl NPF, there were 31 deaths.
Elsewhere, we discuss how we revised our strategy of treating radiation and nuclear accident victims, based our experiences in Chernobyl, Goiania (Brazil) and Fukushima (Bulletin of Atomic Scientists)2.
I must correct several important errors in the miniseries regarding medical effects of radiation exposure.
First, the effects are portrayed as something horrendous, unimaginable. This is inaccurate.
In doing hematopoietic cell transplant, we commonly expose people to much higher radiation doses than were received by 90% of the Chernobyl victims. So do radiation therapists. We know what the toxicities are and we are reasonably effective in mitigating them.
Another error was to portray the victims as being dangerously radioactive. Most radiation contamination was superficial and relatively easily managed by routine procedures. This is entirely different than the Goiania accident, where the victims ate 137-cesium and we had to isolate them from most medical personnel.
Lastly, there is the dangerous representation that, because one of the victims was radioactive, his pregnant wife endangered her unborn child by entering his hospital room. First, as discussed, none of the victims were radioactive—their exposures were almost exclusively external, not internal. More importantly, risk to a fetus from an exposure like this is infinitesimally small.
For example, amongst the several hundred pregnant women exposed to high-dose radiation from the A-bombs, there were only 29 children with attributable developmental defects. All were exposed in the second trimester, when cells are migrating to the brain from the neural crest. We estimate incorrect advice from physicians regarding the relationship between maternal radiation exposure from Chernobyl and birth defects resulted in more than 1 million unnecessary abortions in the Soviet Union and Europe. Ignorance is dangerous.
The solution was for Vorobiev and I to inject one another with sargramostim. We lived, and so, we got permission to proceed.
Producing electricity is also dangerous, but not only from nuclear energy. Although the 31 immediate Chernobyl-related deaths are sad, the number of fatalities is remarkably small, compared with many energy-related accidents, such as the 1942 Benxihu coal mine disaster in China, which killed about 1,500 miners, and the 1975 Banqiao dam accident, also in China, which killed about 250,000 people.
About 15,000 people die mining coal every year, although the true number may be much higher, and this figure does not consider morbidity from occupational hazards such as coal workers’ pneumoconiosis (black lung disease). About 1 million Egyptians are estimated to have become blind from trachoma because of construction of the Aswan High Dam. For reference, about 400 Americans are estimated to die on the highway over Memorial Day weekend.
A final word about how the Soviet government responded to the need for foreign medical assistance. As I wrote, I was immediately invited to come to Moscow and shortly thereafter, to bring three colleagues. In my experience dealing with nuclear accidents, this is rather unusual and indicates a desire to do everything possible to help the victims—throwing politics to the wind.
Would the U.S. have invited Soviet specialists to deal with a major nuclear accident during the Cold War?
Unlikely. Even more extraordinary, when I requested the Soviets allow me to bring in an Israeli scientist to help (there were no diplomatic relations with Israel at the time), they agreed, albeit with a bit of arm-twisting. And whilst in Moscow, we were free to expropriate supplies and equipment from many Russian medical centers. Again, while not a Soviet apologist, the policies I describe are high-minded and praiseworthy.
In the next installment, I will discuss a subject of great current interest and substantial misunderstanding—long-term medical consequences of the Chernobyl NPF accident.
References
Baranov A, Gale RP, Guskova A, Piatkin E, Selidovkin G, Muravyova L, Champlin RE, Danilova N, Yevseeva L, Petrosyan L. 1989. Bone marrow transplantation after the Chernobyl nuclear accident N Engl J Med;321:205-12.
Gale RP, Baranov A. If the unlikely becomes likely: Medical response to nuclear accidents. Bulletin of the Atomic Scientists. March 1, 2011
