If viewed as drama, HBO’s Chernobyl miniseries, an account of the root causes of the tragic nuclear accident and its consequences, was excellent. The narrative was splendid; the depiction of the Soviet Union, which I visited on many occasions, was completely believable. It was also very good on the pitfalls of the Soviet society, particularly the nature of its management and political cultures. And it faithfully portrayed the heroism of many of those involved – not only the ordinary citizens but also some members of the nomenklatura.

However, in the way the show explained the science of nuclear safety and the health consequences of the accident, Chernobyl was grossly misleading. Acute radiation sickness and radiation trauma leading to death are extremely rare. After Hiroshima and Nagasaki fewer than 200 people died because of these conditions. They are so unusual, in fact, that nowadays only big countries with large militaries and or civilian nuclear programmes have the capacity and experience to treat those afflicted.

In addition to these immediate effects, ionizing radiation somewhat increases the risk of cancer later in life. We know this because those who survived the atomic bombings have been extensively monitored by American and Japanese scientists, right up to this day. The study cohort of 120,000 survivors received radiation doses ranging from more than one Gray (5–6 Grays over the whole body is the level which starts to cause fatalities) down to those who had escaped exposure entirely: those who were out of town or were protected by rock or concrete structures. From this work, we now know that the risk of developing a solid tumour is 20% higher among those exposed to the radiation burst than in non-exposed groups (by contrast, life-long smoking increases cancer risk 10- to 20-fold). One in ten of the solid tumours found in the survivor cohort was attributable to the atomic bombs. In other words, most people who survived the bombs had normal lifespans. One unfortunate man was in Hiroshima when the bomb exploded, but survived and fled to relatives in Nagasaki, arriving just before the bomb exploded there. He died in 2010 of stomach cancer (the most common cancer in Japan), having reached the age of 93.

So now to the Chernobyl miniseries. My first objection is to the claim, made in the second episode, that if rescuers had not been able to open water valves in the reactor basement there would have been an atomic explosion, which would have made large parts of Eastern Europe uninhabitable. This is absurd. The uranium or plutonium fuel in a civilian nuclear reactor is enriched to only around 4%. This is far below the level required for detonation. What happened at Chernobyl was a steam explosion.

The portrayal of those affected by the accident was mostly poor. Medically, the most believable scenes were of people vomiting in response to high radiation exposures. The show made much of radiation burns, although these deaths seem much less dramatic once we compare them to normal burn victims, of which there have been millions across the course of human history. There is little to choose between the suffering of those afflicted by radiation burns and burns caused by flames. However, although radiation burns were indeed a major cause of death, the programme inaccurately portrayed the victims as being like zombies from a horror movie. This was “artistic licence”, not fact. Moreover, according to an American colleague who treated some of the victims, rescuers were exposed only superficially; after washing the contamination away, they were no longer contagious. So the suggestion in Chernobyl that a nurse would have told the pregnant wife of a dying rescuer not to touch him is false. Moreover, the death of her baby, shortly after delivery, was blamed on radiation exposure, a claim that is clearly nonsense, because if the exposure was fatal to the baby in the womb, it would certainly have killed the mother too.

In another case of the need for dramatic impact overwhelming any desire for factual accuracy, the official in charge of the rescue mission would not have been told that he would die of bone marrow cancer, as there would be only a chance of that happening, not a certainty. When another official was portrayed as having become ill within a few years of the accident, it was implied that this was as a result of radiation exposure. But in Hiroshima, the excess leukaemia cases (just 80 of them) occurred at least five years later.

At the end of the last episode, there was a summary of the health consequences of the accident, the central proposition of which was that 40–90,000 people died. The number is ludicrous, and can only have been reached by incorporating estimates of how many cancers would develop, and by assuming that even those who received very low exposures would be adversely affected too. This is the so-called “linear no-threshold dose-response model”, the highly precautionary approach that has been the basis of nuclear regulation for decades (although not sufficiently precautionary to satisfy environmental campaigners, who have long tried to justify more extreme models).

It is true that there was an unexpected thyroid cancer epidemic among children and adolescents. This has now affected 20,000 individuals, and one in four thyroid cancer patients in the most-affected areas can blame their illness on the accident. However, in Chernobyl, HBO did not tell the whole story.

Firstly, the Soviet leaders kept the accident a secret for seven days. The delay led to considerable harm, for example the children who received massive radiation doses from contaminated milk. Such secrecy is only possible in an authoritarian society.

Secondly, in the worst affected areas, goitres are endemic. This condition, which causes the thyroid to swell, enhances accumulation of radioactive iodine there. In other words, the people in the Chernobyl area were more susceptible than people in other parts of the world would have been.

Thirdly, and most unethically, the miniseries did not mention that only a tiny fraction of these thyroid cancer cases have been fatal. Up to 2010, only 15 people had succumbed.

The show also claimed that the hundreds of thousands of workers who were involved in the clean-up process have not been monitored. This is simply untrue. Most have been studied intensely, with no adverse health consequences attributable to radiation having been detected.

Chernobyl was entertaining as drama, but worse than useless in portraying the facts of nuclear safety. In a world that desperately needs low-carbon energy, this sort of scaremongering is unethical. The record needs to be put straight, but the media have little interest in telling the dull truth.

Mikko Paunio is an epidemiologist based in Helsinki. He has been the Chairman of the Radiation Safety Board of Finland, nominated by the Council of State (Cabinet), since 2009