The events of 26 April, 1986, changed the lives of millions of Ukrainians, and people beyond Ukraine’s borders, when Reactor 4 of the Chernobyl Nuclear Power Plant underwent a catastrophic failure during a safety test. RFI spoke with Dr Andrei Kindzelski, son of Professor Leonid Kindzelski, chief radiologist of the Ukrainian Soviet Socialist Republic, who in 2021 was awarded the title Hero of Ukraine in recognition of his tireless efforts to save the lives of those affected.
The failed safety test at Chernobyl caused a massive power surge, leading to two explosions which severely damaged the reactor's core, releasing radioactive nuclides into the atmosphere and causing widespread contamination of the surrounding land – and long-term harm to human health, the effects of which are still being felt today.
The disaster was unprecedented, leaving a declining Soviet regime to deal with what remains the worst nuclear disaster in history.
Hundreds of thousands of responders were mobilised – engineers, firefighters, medical personnel, soldiers and police officers, as well as plant workers – from the very first hours following the explosion, and throughout the years that followed.
Among the early medical responders was Professor Leonid Kindzelski, chief radiologist of the Ukrainian Soviet Socialist Republic, as the country was called at the time. He is a figure well known among Chernobyl survivors, but far less recognised outside Ukraine.
He played a key role in treating victims of acute radiation sickness in the immediate aftermath, introducing then-innovative approaches such as bone marrow transplantation and intensive detoxification methods.
While his work is credited with saving numerous lives among the first groups of firefighters and plant workers, a fact corroborated by survivors, he received little recognition during his lifetime. He also suffered from radiation exposure, but continued working in oncology and radiology until his death in 1999.
In 2021, Ukraine's President Volodymyr Zelensky posthumously awarded him the title of "Hero of Ukraine" – the country’s highest honour for civilians – in recognition of his tireless efforts to save the lives of those affected by the Chernobyl disaster.
Forty years on from the disaster, RFI spoke with Andrei Kindzelski, the son of Leonid Kindzelski, who now lives and works in the United States as a haematologist and branch chief at the National Institutes of Health.
Having been a first responder at Chernobyl himself in 1986, when he was a medical student, he shared his recollections of the time and of his father’s work.
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RFI: What are your memories of that time? Were you immediately aware of what had happened?
Andrei Kindzelski: On 26 April, 1986, we did not know there had been an explosion at the Chernobyl nuclear station, we first received news that my father had been arrested.
My mother called us to tell us that while they were at our country house, a black car with two men in suits arrived. They approached my father, grabbed him, made him get into a car, and he disappeared.
It was related to Chernobyl, but at that moment we did not know it. The only news was that my father had been arrested. The next day we heard from him, and news of the explosion at the nuclear power plant had already spread – word of mouth worked very well in the former Soviet Union, as a compensation for media censorship.
My father called me and said only a few words: "I am fine. Take two drops of over-the-counter iodine, put them in a glass of milk and drink it immediately. Tell everyone you can reach to do the same."
And that is all I heard from him for days. We did not communicate any more at the very beginning, because at that time I had been told to go to Chernobyl as a fifth-year medical student, otherwise I would not have obtained my medical degree. For two weeks, I was practically unreachable, because I was in that zone.
I learned that my mother, who was a professor of haematology, had been asked at that time to provide a laboratory technician from her team to be sent to Chernobyl to manually count on site the white blood cells of the rescuers working there.
She called me before my departure and told me she could not send any of her employees, because they were all young women of childbearing age. So she went there herself and spent three weeks in Chernobyl, sitting at the microscope counting the white blood cells of the rescuers.
Upon my return from Chernobyl, I communicated daily with my father. At that time, his clinic was operating at full capacity – it was a difficult period for everyone. My father practically lived at work. His office had a small room at the back, just big enough for a small sofa, and that is where he spent most of his nights. From the beginning, with the arrival of irradiated patients, the majority of his colleagues self-mobilised – they were ready to do anything to help them.
At that time I saw my father every day, because I was irradiated and he provided me with care – mainly dialysis to eliminate the radionuclides I had absorbed.
My father was very focused. He had one goal – to help patients as much as possible. He was literally risking his career, his position, his medical degree, his freedom by doing what he believed was right.
The pressure on him was enormous, and it came not only from the Ukrainian Ministry of Public Health but also from Moscow, from Russia. He was under daily criticism from important figures who were trying to prevent him from continuing his work. It was very hard for him, but he was very, very strong.
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RFI: The most severely irradiated patients – around 70 people – were hospitalised in Moscow, at Clinic No. 6, and in Kyiv, at your father’s clinic. He was facing an unprecedented situation and had to make decisions quickly and under intense pressure. Can you describe what that was like?
AK: He was absolutely certain about what he was doing medically and scientifically, but one must not forget that Chernobyl happened under the Soviet Union, and the system was designed in such a way that it was impossible to deviate from protocols. It did not matter whether it was beneficial or not for the patient, nothing different could be done.
The other element was the enormous political pressure. The problem is that, once the planes landed in Moscow, the Minister of Public Health of the Soviet Union officially declared that all severely irradiated rescuers had been hospitalised at Clinic No. 6 in Moscow. Gorbachev repeated this publicly on television. From that moment on, the patients who remained at my father’s clinic in Kyiv became illegal. They were not irradiated since "all patients had been evacuated and hospitalised in Moscow".
My father was forbidden to write "acute irradiation" in his diagnoses. He could not write it. Different words were used to describe the same thing. It was forbidden to perform bone marrow transplants. He used a particular language to explain that the simple administration of donor bone marrow to the patient does not constitute a full transplantation, because the existing bone marrow is not destroyed by chemotherapy.
He was constantly monitored by the KGB, and my mother expected that my father would be arrested, if not today then tomorrow. She had prepared two small suitcases, containing what was needed for an initial incarceration. One was at home and the other in my father’s office, in case he was arrested at work.
My father’s clinic implemented a strategy: every night, the medical files of irradiated patients were taken home by a different person. This way, they would not risk being altered or stolen, or disappearing.
My father was dismissed from his administrative position, that of Head of the Nuclear Medicine Department of the Ministry of Public Health of Ukraine – or more simply, chief radiologist.
This was probably due to his resistance, but the final doubt was removed when he refused, during a televised interview, to say that everything was fine, that there was no radiation and no danger to the population.
RFI: What about those irradiated patients? Were they aware of the gravity of their situation?
AK: There was an incident where patients who were colleagues, sometimes brothers, were separated: a group of patients was transferred to Moscow, while another ended up in the hospital in Kyiv.
At that time people communicated by telephone, and patients did as well. And of course, the announcement of the death of their Chernobyl colleague in the Moscow hospital created a very difficult situation for the patients in Kyiv.
Local patients came to see my father and asked him: "If my colleague, my brother, has already died in Moscow, when am I going to die?” When he told them 'you are not going to die, you are going to recover', they did not really believe him, because it is hard to do so when you see your loved one die.
My father organised a fundraising effort with his team members and sent someone to buy men’s clothing, because the patients’ clothes had been buried, as they were radioactive. The new clothes arrived, and for the patients it was such a comforting thing – that someone would spend money on civilian clothes meant for them that they were going to get out of there and survive.
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RFI: Can you explain the difference between the protocols used in Moscow and the treatment given in Kyiv by your father?
AK: The treatment in Moscow followed international protocols, and these protocols are still in force. For example, during the Fukushima nuclear accident [in March 2011 in Japan], the same international protocols as those used in Moscow during Chernobyl were applied.
These protocols were developed from experience gained in treating patients with acute leukaemia, with a bone marrow transplant. To prevent rejection, bone marrow containing cancer cells and blood cells is irradiated to kill the cancer cells and to avoid incompatibility between donor and recipient bone marrow. To prevent rejection of donor bone marrow, a specific drug inhibiting the immune response is used. This has a very strong inhibitory effect on the bone marrow. Then the donor bone marrow is introduced into the patient’s body.
This is roughly how the patients in Moscow were treated. They were irradiated in Chernobyl, then received immunosuppressive treatment to prevent rejection of donor bone marrow, and then the bone marrow transplant was performed, in the hope that the patient would survive.
My father had a different and very firm opinion on this issue, and cited the early bone transplantation approach of Dr. Georges Mathé of France. He considered the fact that these firefighters were young men, in perfect health, without any tumours or malignant cells that needed to be killed. Traditional bone marrow transplantation accounts for complete destruction of the recipient’s bone marrow in the hope that the donor’s will take over.
The most important thing for him was to cover the period during which the patient’s irradiated bone marrow no longer produces blood cells. Without the added step of administering a drug inhibiting the immune response and killing more of the recipient’s bone marrow cells, the donor’s bone marrow will temporarily function, but later will likely be rejected. He believed it was possible to medically manage the later rejection of donor bone marrow.
For all his patients who underwent bone marrow transplantation, he only performed a partial transplant, until the patient’s own marrow became functional again and rejected the donor marrow. It is manageable – it is painful, it is unpleasant, but the rejection process is manageable. Thanks to this, almost all 35 patients survived.
One patient died, but he had not received a bone marrow transplant – the level of radiation he had received was several times higher than the lethal level, nothing could be done to save him.
The second approach introduced by my father consists of eliminating as many radionuclides as possible from the body. This is what he did with me. He introduced haemadsorption and enterosorption, which work by administering special compounds that eliminate heavy metals, radioactive particles and metals from the bloodstream.
RFI: At what point did Professor Kindzelski know that his patients were out of danger? And once they had been saved, how could Moscow hide them?
AK: Moscow can hide many things, and this was one of them. For the Russian political leaders of the time, it was shameful to admit that irradiated patients had died in Moscow and survived in Kyiv.
As a result, until the collapse of the Soviet Union, my father was practically unable to publish anything, because all scientific publications were controlled. Medical journals did not respond to him, or responded that [his work] was off-topic. In addition, my father tried to present his work at international conferences. And during the time of the Soviet Union, he was not allowed to leave the country.
After the collapse of the Soviet Union, the pressure persisted. [While] he could attend international conferences, the committee [responsible for selecting speakers for these conferences] was composed of representatives of the Russian medical elite, and systematically rejected his presentation on a new therapeutic approach for irradiated patients.
I remember at least one case where he went to a conference in Prague to present a treatment for lymphoma using sublethal doses of radiation. Once at the podium, he said: “I will not talk about lymphoma, I will talk about my experience in treating patients with acute radiation syndrome after Chernobyl because I want to share this experience."
The other problem is that medicine is very conservative, and when one performs a bone marrow transplant without adequate preparation according to international protocols, one knows that one exposes the patient to a very serious risk: rejection of the donor bone marrow.
And it is very difficult for the doctor to know that he or she is willingly harming the patient, even temporarily. This is justified for severe radiation exposure because, in most cases, the patient will probably survive. But it is a risk. And even today, it remains a practice outside protocol.
RFI: Did your father receive support from Western colleagues?
AK: He was sidelined by his Western colleagues – to the point that my parents pooled together their scientific experience acquired during the Chernobyl disaster to compile it into a book and have it published, but no one wanted it. Our family ended up financing the publication of this book. We sent it to university and medical libraries around the world in order to preserve this information and prevent it from being forgotten.
RFI: How was life for your father in the years following the disaster? It must have had a considerable impact on him...
AK: Absolutely. First of all, it is very difficult to live under constant pressure and stress.
Secondly, in the days following his disappearance, my father told me that as chief radiologist of the Ministry of Public Health of Ukraine, he had the mission of determining the radiation levels and types of isotopes emitted by the reactor within a 10-30 kilometre zone around the Chernobyl nuclear plant. He had only a few people to help him. He was alone with the dosimeter; they went with his driver to different places, near and far from Chernobyl.
One of his discoveries in the first days was very important: the radiation level is not uniform, it is very irregular from one place to another. A dangerous level of radiation can become almost normal 50 or 100 metres away. It was not known that this could happen.
During this period, he was irradiated. He had nosebleeds, probably linked to his platelet count, and he contracted a respiratory infection – these are symptoms of radiation exposure. Later, his health deteriorated. He eventually developed cancer. He died in 1999.
RFI: During those later years, did you talk about the disaster?
AK: In the last months of his life, I was by his side and we talked a lot, especially him. Chernobyl was a daily subject of our conversations.
He never thought he had acted wrongly, because the results spoke for themselves. What tormented him was the impossibility of changing the system and introducing this approach in similar future disasters. This affected him greatly – and me as well later, when the Fukushima nuclear accident happened. Nothing from my father’s experience was used to treat patients there.
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RFI: Your father died before his work was recognised by the Ukrainian state...
AK: Yes, he died 13 years after the Chernobyl disaster, and 22 years passed before he received the title of Hero of Ukraine.
I know it is important to be recognised during one’s lifetime, but awarding a distinction to a doctor who did his job, and did it very well, is very important and entirely appropriate in my view. I am grateful to Ukraine and to the survivors who remembered him and who requested this honour.
What was very touching is that he received his title in the autumn of 2021, and at the end of 2022 we went to the Ukrainian embassy in Washington to receive his decoration. It's incredible – a country at war, fighting for its survival, finds the time and means to send this decoration across the world to honour a person who deserves it. It is an extraordinary country: you cannot win a war against this country.
