Scott D. Pierce: HBO’s ‘Chernobyl’ is horrific and devastating. You should watch it.

(Photo courtesy Liam Daniel/HBO) Stellan Skarsgård, Jared Harris and Emily Watson star in “Chernobyl.”

However bad you think the Chernobyl nuclear disaster was, it was worse. And HBO’s five-part miniseries about it is the grimmest thing you’ll see on TV this year.

Re-creations of men dying of radiation poisoning are absolutely horrific. Stomach churning. They make all the violence and death on “Game of Thrones” pale by comparison.

“Chernobyl” recounts what came perilously close to being the worst “accident” in human history. It could have wiped out millions of people and rendered thousands of square miles uninhabitable for years, centuries, millennia.

And it was 100 percent caused by human mistakes and incompetence. The nuclear power plant’s design was unsafe, and the explosion and meltdown came after plant personnel violated protocols and procedures during a test, intentionally shutting down the emergency systems. Plant personnel thought a failsafe system would work; it didn’t. It couldn’t.

“When you watch the series, you will realize how difficult it is to make a nuclear reactor explode,” said executive producer/writer Craig Mazin. And that catastrophe was compounded by “errors in judgment and intentional lies and dissembling from levels from the very top all the way down to individual people in a room.”

And he wasn’t talking about the top management at the plant, he was talking about the leader of the Soviet Union himself, Mikhail Gorbachev (David Dencik), and his direct subordinates. Among the primary players in “Chernobyl” is Stellan Skarsgård as Deputy Prime Minister Boris Shcherbina, who is initially more concerned about the reputation of the USSR than the safety of his people.

He refuses to listen to nuclear physicist Valery Legasov (Jared Harris), and threatens him with arrest and others with execution. Another nuclear physicist, Ulana Khomyuk (Emily Watson), is jailed by the KGB. Decisions are made based on politics, not science. And Shcherbina turns out, eventually, to be one of the good guys.

“Chernobyl was the product of intentionally terrible decisions designed to protect a system that was inherently corrupt and inhumane,” Mazin said.

(Photo courtesy Liam Daniel/HBO) Stellan Skarsgård, Jared Harris and Emily Watson star in “Chernobyl.”

The narrative “is as close to reality as we can get and still be able to tell the story in five episodes,” he added. “The simple rule that we had — if we were going to change something, it had to be only so that we could tell the story fully. We never changed anything to make it more dramatic than it was.”

There was no need. Reality was dramatic enough. But getting to the truth wasn’t always easy, because Chernobyl happened in a nation that “was not particularly known for its openness,” Mazin said.

He turned to books written by Soviet scientists, nine reports by the International Atomic Energy Agency and first-person accounts. He researched what life was like in Soviet Ukraine at the time. “We want to be accurate in all regards, down to the shoelaces that people are wearing,” Mazin said.

The series was filmed, in part, at the Ignalina Power Plant in Lithuania — which was of the same design as Chernobyl. (The European Union made shutting it down a condition of admitting Lithuania.)

What makes “Chernobyl” all the more horrifying is that it isn’t an over-the-top drama. It’s often spare and matter-of-fact, but the facts are ghastly and gruesome.

There’s no dialogue, no hysterical weeping as radiation victims are buried in lead coffins, which are then encased in concrete as somber music plays. A young soldier has to kill pet dogs who have been exposed to radiation. A young woman’s unborn child somehow absorbs the radiation that would have killed the mother. Workers enter the plant in an attempt to avert complete disaster with the knowledge that their chances of survival are slim to none.

Why watch something as grim as “Chernobyl”? It's gripping, but it's impossible to call it entertaining.

And yet there are heroes among the villains and the victims, and their stories were “oddly beautiful,” Mazin said.

“In response to what I would consider to be the worst of human behavior, we saw the best of human behavior. Only humans could have made Chernobyl happen, only humans could have solved the problem of Chernobyl,” he said. “The quiet nobility of hundreds of thousands of people, names of whom we will not know, is remarkable.”

And “Chernobyl” stands as a warning, not just for the former Soviet Union — where 10 Chernobyl-type nuclear power plants still operate today (albeit updated) — but for the rest of the world. And not just about nuclear power.

“The cautionary tale here is about what happens when people choose to ignore the truth,” Mazin said. “As it turns out, the truth does not care. The world gets hotter whether we agree with it or not, and that is something that I hope people can take away from the show.

“It’s our hope ... that we can popularize this story to the extent that maybe somebody in a position of power might think twice.”