• The HBO series “Chernobyl” gets plenty of things right about the nuclear power plant disaster that most likely exposed hundreds of thousands of people to radiation.
  • But to adapt the story for television, the “Chernobyl” writer and producer Craig Mazin invented a character and adjusted the chronology of a few events.
  • While some circumstances are still shrouded in mystery, we now know the incident was far more catastrophic than Soviet officials initially let on.
  • The miniseries is nominated for 19 Emmys. The award show will be held Sunday, September 22.
  • Visit Business Insider’s homepage for more stories.

Retelling the 1986 Chernobyl disaster is an exercise in unburying the truth.

The world’s worst nuclear power plant accident forced the city of Pripyat, in what was then part of the Soviet Union, to evacuate after being exposed to toxic levels of radiation. In its wake, Soviet officials publicly downplayed the incident. To this day, scientists are still working to understand the effects of the fatal explosion.

Read more: ‘Apples the size of watermelons’: A psychologist reveals what it was like to grow up in the Chernobyl fallout zone

What we do know is that the core of a nuclear reactor opened, sending plumes of radioactive material into the air. The toxic fumes not only contaminated the local vegetation and water supply but also poisoned nearby residents, some of whom went on to develop cancer.

Within three months of the disaster, more than 30 people had died of acute radiation sickness.

"We can only estimate the real effects on people's lives," said Jan Haverkamp, a senior nuclear energy expert at Greenpeace, who noted the catastrophe most likely had a severe impact on hundreds of thousands of people.

While developing his HBO series, "Chernobyl," the writer and producer Craig Mazin approached conflicting accounts of the event with a degree of caution.

"I always defaulted to the less dramatic because the things that we know for sure happened are so inherently dramatic," he told Variety's "TV Take" podcast.

The miniseries earned 19 Emmy nominations, including in the Outstanding Limited Series category, in which it's considered a frontrunner. The award show will be held Sunday, September 22.

For the most part, it's hauntingly accurate - with the exception of a few artistic liberties. We fact-checked some of the major plot points from the series to determine what's true and what verges on myth.

Note: This article contains spoilers of episodes one through five.

MYTH: The Chernobyl fire gave off nearly twice the radiation of Hiroshima every hour.

Foto: sourceLiam Daniel/HBO

Both Chernobyl and the bombing of Hiroshima, Japan, during World War II were catastrophic nuclear disasters. But Haverkamp said it's difficult to compare the radiation exposure of the two events.

With Hiroshima, he said, the major health impact was caused by direct exposure to radiation. When a nuclear bomb explodes, he said, a person's radiation dose is determined by the person's distance from the point of exposure.

In Chernobyl, he said, "a lot of radioactive material was brought into the atmosphere." The material, he added, was then "spread over a very large area" and ingested by people over a long period of time.

Read more: Russia still has 10 Chernobyl-style reactors that scientists say aren't necessarily safe

FACT: The Soviets tried to use robots to clean the contamination site but eventually resorted to human labor.

Foto: Sumpter on HBO's "Chernobyl" miniseries.sourceLiam Daniel/HBO

In a horrifying scene in episode four, men throw blocks of radioactive graphite off the roof of the power plant - what the series calls "the most dangerous place on earth." In real life, the men were asked to clear 100 tons of radioactive debris from the area.

At a conference in 1990, the official who oversaw the cleanup efforts, Yuri Semiolenko, said the Soviets had initially tried to clear the site with remote-controlled robots. When the machines started breaking down in the toxic atmosphere, officials resorted to human labor.

Though advanced US robots could have aided the decontamination, tensions between the two countries dissuaded Ukraine from asking for help.

MYTH: A Soviet nuclear physicist named Ulana Khomyuk helped orchestrate the cleanup.

Foto: sourceLiam Daniel/HBO

One of the series' main characters, a Soviet nuclear physicist named Ulana Khomyuk, is an amalgamation of many nuclear scientists involved in the Chernobyl cleanup.

For Mazin, placing a female character at the heart of the investigation made historical sense.

"One area where the Soviets were actually more progressive than we were was in the area of science and medicine," Mazin told Variety. "The Soviet Union had quite a large percentage of female doctors."

Read more: HBO's 'Chernobyl' series invented a main character to depict the world's worst nuclear power plant accident

FACT: Squads were ordered to shoot animals, which carried elevated levels of radiation.

Foto: sourceLiam Daniel/HBO

One of the most harrowing scenes arrives in episode four, "The Happiness of All Mankind," when a three-person Soviet squad is tasked with shooting stray animals near the reactor site.

About 36 hours after the explosion, Pripyat residents were given just 50 minutes to gather their belongings and board the throngs of buses that had come to take them away. None were allowed to bring their pets.

Residents initially believed that they would return after three days, but the move turned out to be permanent. As orphaned dogs wandered the abandoned city, Soviet squads were ordered to kill them to avoid the spread of contamination.

About 300 stray dogs remain in the Chernobyl exclusion zone, but few live past the age of 6 because of predation and harsh winter conditions.

MYTH: A steam explosion following the disaster could have left much of Europe uninhabitable.

Foto: sourceLiam Daniel/HBO

In the wake of the initial blast, nuclear physicists feared a second explosion caused by melting corium coming into contact with groundwater.

In episode two, Khomyuk informs the USSR that a follow-up explosion would carry a force of 2 to 4 megatons, which would wipe out "the entire population of Kiev and a portion of Minsk." The release of radiation, she adds, would "impact all of Soviet Ukraine, Latvia, Lithuania, Belarusia, Poland, Czechoslovakia, Hungary, Romania, and most of East Germany."

Haverkamp said there were too many hypotheticals considered in this scenario.

"They're not saving the world," he said. "That situation might play out if all of the melting corium hit groundwater," he added, but when corium starts melting, it melts "in a very uneven way."

The claim that a second explosion would carry a force of up to 4 megatons, he said, was "an exaggeration."

FACT: A young firefighter with a pregnant wife died in a hospital shortly after the explosion.

Foto: sourceLiam Daniel/HBO

A firefighter named Vasily Ignatenko and his wife, Lyudmilla, were scheduled to leave for Belarus the morning of the explosion, but their plans were curtailed when Vasily rushed to the power plant at about 1:30 a.m. He promised to wake his wife when he got home, but his severe radiation poisoning forced him to be taken to the hospital.

When Lyudmilla visited her husband, she was ordered not to touch him. "If you start crying, I'll kick you out right away," she recalled being told in the book "Voices from Chernobyl."

Lyudmilla was pregnant at the time but lied to the radiologist to see her husband. Vasily died 14 days after the accident and was buried, as the series shows, in a zinc coffin. The documentary even shows Lyudmilla carrying her husband's shoes, which couldn't fit around his swollen feet.

Lyudmilla eventually gave birth to her baby, who died after four hours.

MYTH: A helicopter crashed shortly after the explosion.

Foto: sourceLiam Daniel/HBO

The helicopter crash in episode two isn't all wrong, but it took place after the initial two weeks of recovery - not, as the episode suggests, in the immediate wake of the explosion. In a statement to Men's Health, Mazin said it was one of the few events that had to be moved around chronologically.

"I wanted people to know that this was one of the hazards that these pilots were dealing with - an open reactor. Radiation was flying over it," he told the site.

The series shows the helicopter colliding with a crane and cascading to the ground - an event that's represented even more dramatically in real-life footage.

Haverkamp said the air movements surrounding the reactor were unpredictable, but what caused the crash "was indeed hitting the crane."

FACT: Legasov recorded his thoughts on cassette tapes following the disaster.

Foto: sourceLiam Daniel/HBO

Chernobyl's chief scientific investigator, Valery Legasov, was a real person. While the series portrays the scientist as something of a lone wolf, he actually had a wife and daughter.

As the opening episode reveals, Legasov recorded his personal account of the disaster on cassette tapes before hanging himself on April 26, 1988 - the second anniversary of the accident.

Transcripts of his recordings don't exactly match up with those relayed in the series, which ends with a line from Legasov: "This, at last, is the gift of Chernobyl. Where I once would fear the cost of truth, now I only ask: What is the cost of lies?"

Toward the end of episode five, a KGB official informs Legasov that his involvement in the cleanup efforts will be kept quiet from the rest of the world.

"You will remain so immaterial to the world around you that when you finally do die, it will be exceedingly hard to know that you ever lived at all," the official says.

According to Legasov's obituary in the New York Times, the scientist's name "was not mentioned in the dozens of Soviet media reports" on Chernobyl's second anniversary.

Correction: An original version of this article misrepresented the cause of the helicopter crash in the HBO series. The article has also been updated to reflect the cause of the low life expectancy of Chernobyl's stray dogs.