HBO’s fascinating and necessarily bleak miniseries “Chernobyl” is every bit as grim as it looks — maybe even grimmer than that. How could it not be?

It takes viewers back to the Ukrainian town of Pripyat in the early morning hours of April 26, 1986, when an explosion occurs at the Chernobyl Nuclear Power Plant, showering the site with radioactive chunks of graphite and releasing a toxic plume that put much of Western Europe, Scandinavia and the western side of the Soviet Union at risk for deadly contamination.

Workers scramble to prevent further damage to the reactor’s core; local firefighters rush to the blaze (and, for many of them, eventual doom); residents gather on a nearby bridge to get a better view of the glowing flames in the distance while their children play in a gentle sprinkling of toxic ash.

It’s a hideous and haunting sight, from start to finish. Chernobyl’s human toll is still unknown – this effective, no-nonsense and highly researched dramatization estimates deaths anywhere from 4,000 to 93,000 over the past 33 years. (An official count, left over from Soviet authority, is still just 31 dead.)

Depressing as it may be, “Chernobyl,” created and written by Craig Mazin and directed by Johan Renck, is a fine study in the uses of sanctioned obfuscation — and how much easier that becomes in a country where media and scientific leadership are tightly restricted. There was a time when that sort of thing might have seemed entirely foreign to an American audience; now, it’s another resonant alarm sounding uncomfortably close.

While the Soviets are able to keep the news from leaking for a couple of days, the internal panic about a bigger, imminent explosion spreads up the chain of command to an aghast Mikhail Gorbachev (David Dencik), who immediately assigns his brash deputy prime minister, Boris Shcherbina (Stellan Skarsgard) to travel to Pripyat with the U.S.S.R.’s leading nuclear physicist, Valery Legasov (Jared Harris of “Mad Men”), to oversee the effort to fight the fire at the plant and mitigate further contamination.

Initially at odds (“Tell me how a nuclear reactor works or I’ll have one of these soldiers throw you out of the helicopter,” Shcherbina says to Legasov on the flight to Chernobyl), the two men unite over the desperate goal of keeping the eastern part of the continent from becoming a radioactive wasteland.

Much of “Chernobyl” is preoccupied with the quiet traces of heroism and dignity that faced down the corruption and dishonesty that defined Soviet life. A subplot involves the determination of a young woman (Jessie Buckley) who risks her own health to be with her husband (Adam Nagaitis), a firefighter who experiences an agonizing death from radiation burns. A group of surly miners agree, for the greater good, to dig an emergency tunnel beneath the damaged reactor. Emily Watson co-stars as physicist Ulana Khomyuk, a composite character who stands in for the many Soviet scientists who jeopardized their careers to discover the truth about what happened at Chernobyl.

The performances are engaging, verging here and there on superb (if sometimes too distractingly British in accent), and there’s a familiar, drab despair that assures us we’re back in the U.S.S.R. — perhaps deep into some lost, digressive season of FX’s much-missed drama “The Americans.” Contrary to some advertising that makes “Chernobyl” look like a fast-paced Cold War thriller with gross-out consequences, it is instead more committed to a disciplined, truthful and scientific account. That’s both commendable and not always exciting.

The disaster, it turns out, was attributable to human errors, stemming from an unnecessary stress test ordered by the reactor’s bureaucrats. The series works its way to a trial that tries to pin the blame on a few key players; it is Legasov’s outspokenness that indicts the entire system.

If you watch all this and still feel somewhat numb to the event’s lasting toll, perhaps the dead dogs will get you. In “Chernobyl’s” fourth episode, a young Soviet conscript named Pavel (Barry Keoghan) is assigned the daily task of shooting all of the region’s abandoned canines, piling their bodies into a truck and dumping them into open graves, which are then filled with cement. I mention it because that’s what it takes, sometimes, to shake an audience out of its stupor: A contamination lasting thousands of years? (Yawn.) A chunk of Europe and Russia coming close to being forever lost? (Whatever.) The human deaths? (Nah.)

The massacre of dogs, though? Even the puppies?

Something tells me HBO is in for some 2019-style fallout.

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“Chernobyl” is one hour in length. The first of five parts premieres Monday at 9 p.m. on HBO and continues weekly through June 3.