History Daily - The Lake Nyos Disaster

Episode Date: August 21, 2026

August 21, 1986. A rare eruption of carbon dioxide from a mountain lake in Cameroon kills 1,746 people in a single night. Support the show! Join Into History for ad-free listening and more. History Daily is a co-production of Airship and Noiser.Go to HistoryDaily.com for more history, daily.

It's August 22nd, 1986 in Saboom, a village in northwest Cameroon. Joseph Inquine opens his eyes a crack and peers around. It takes him a moment to realize exactly where he is. He's lying on the floor of his hut, and someone is hammering on the door. But Joseph doesn't move. Instead, he just stares up at the ceiling while fragments of the previous night drift back into his memory. He woke in the early hours to a strange smell. and the sound of his daughter struggling to breed.

He rose from his bed to check on her, but his leg suddenly felt weak. Then everything went black. From the bright light seeping around the doorframe, Joseph can tell it's now mid-morning. He must have been unconscious for hours. The knocking comes again. Joseph tries to answer, but his voice is only a croak. Slowly, he clambers to his feet. The movement sends a burning pain across his arm.

and looking down, he sees angry red sores covering his skin, marks that definitely weren't there when he went to bed. Joseph staggers to the door and opens it. He sees it was his neighbor who was knocking, but the man is already shuffling toward the next hut, moving slowly as though every step hurts. Joseph tries to call out, but again, his voice fails him. He looks around. Apart from the neighbor, there's not a soul to be seen. Saboom is a cattle village. Most residents are herders, like Joseph, and usually they're up and about early to tend to their livestock. But not this morning. Today the village is deserted.

Suddenly, the world begins to spin. Sensing he's about to faint, Joseph stumbles back inside, past his daughter lying motionless on her bed, and collapses unconscious again. When Joseph unquine wakes hours later, he makes a horrifying discovery. His daughter is dead, apparently suffocating. in her sleep, and she's not the only sudden, unexpected fatality in the village. Entire families in Suboom have perished overnight, leading just a handful of bewildered survivors, the victims of an invisible natural disaster which swept through this isolated region of Cameroon on August 21, 1986.

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Come see my Days that Made America Tour, live. on stage, go to HistoryDailyLive.com. From Noisor and Airship, I'm Lindsay Graham, and this is History Daily. History is made every day. On this podcast, every day, we tell the true stories of the people and events that shaped our world. Today is August 21, 1986, the Lake Neos disaster. It's the evening of August 21st, 1986, in the mountains of Northwest Cameroon, a few hours before villagers in the region succumb to a mysterious illness. Kaluz Ketu feels his calves burn as he climbs the steep path toward Lake Neos.

It's a route he knows well. He lives in a tiny settlement nearby, a village so small that it doesn't appear on most maps. Like many of his neighbors, Kaluze keeps cattle and farms the fertile volcanic soil. But whenever he can, he hikes up to the lake to cast nets for fish and crabs. The catches are usually poor. Lake Neos fills the crater of an ancient volcano, and its water has an unusual taste, and few creatures seem to be able to survive in it. But tonight, Kaluas isn't here to fish.

Earlier this evening, strange noises echoed down the valley, sharp pops and muffled explosions coming from the direction of the lake. At first, people thought they were gunshots, and as worried neighbors gathered outside their homes, Kaloose volunteered to climb the mountain and investigate. But the hike is harder than usual. The air is still and humid, and Kaluas is soon breathing heavily. The forest seems unusually quiet, too. Normally, insects buzz in the undergrowth and frogs call from nearby streams, but tonight only the crunch of Kaluza's footsteps breaks the silence.

As he reaches the crest of the slope, he crouches low and peers over the ridge, expecting to see the nomadic raiders who occasionally trouble this area. Thankfully, there's no one else here, although the scene is far from tranquil. The water of Lake Neos, normally a deep blue, is now a murky blood red. Near the center, a tower and column of water shoots into the air. It sinks almost back to the surface before erupting once again. This plume rises hundreds of feet before crashing back down, sending waves racing across the lake. And there's also a low mist hanging just above the water and a stench that remains.

reminds Kaloose of rotten eggs and gunpowder. Clusters of dead fish float on the surface, and strange noises seem to echo from the lakebed. Every instinct tells Kaloose that something is terribly wrong, but he has no idea what's caused the sudden change. He can only stand and watch as the water spout rises and falls. Soon he notices that he's no longer alone. Others from nearby villages have climbed to the lakeside too, all drawn by the same unsettling sounds. Some whisper prayers. Others declared that the volcano must have reawakened. As the villagers debate what's going on,

the low-hanging mist begins to drift away from the water and slide down the mountain. A friend from a neighboring village decides he's seen enough and turns toward home. Kaluas watches the glow of his lamp slowly descend before vanishing into the eerie mist. Kaluas refuses to follow because something about this mist feels wrong. Instead, he settles in and waits. For hours, he watches the cloud ebb and flow in the moonlight, and eventually the wind shifts, carrying the mist away from the path to his village. Only then does Kaloose make his way home,

and by the time he reaches his house, it's the middle of the night. He bolts the door behind him and climbs into bed, hoping that the mist won't return. The following morning, the mist is gone, but something still isn't right. The mountain remains eerily. silent, no birdsong, no chirping insects, and even the dogs have stopped barking. Kaluze sets out to check on the friend he watched disappear into the cloud the night before, and when he reaches the neighboring village, he finds a scene of devastation.

Many people are dead, apparently suffocated in their sleep. Kaloose's friend is one of the few survivors, but he sits alone, his eyes raw with tears. His daughter is among the dead. Kaluze stays to help bury this man's child, then helps other fans. families with their dead as well. As the morning wears on, word arrives from other villages across the region, and everywhere the story is the same. Sometime during the night, a strange mist drifted through their homes and cattle pens, silently killing people and livestock alike. It will take days for the news of these deaths to escape this remote corner of Cameroon, and when it does, scientists around the

world will be confronted with one of the deadliest and most baffling natural disasters in African history. It's August 24, 1986, in Cha, a village near Lake Nios, three days after the disaster. A humanitarian worker walks along the dirt road into the village. He's been here before, but it barely resembles the place he remembers. Cha is usually full of life, children playing, women pounding grain, cattle lowing, but now the only sounds are muffled voices, the scrape of shovels, and the buzzing of flies. Everywhere he looks, there are bodies. Birds lie scattered beneath trees as though they simply drop from the sky.

Goats and sheep sprawl across footpaths. Cattle remain where they collapsed inside their pens, and even stray dogs lie motionless beside the road. Then he sees the people. Some have been wrapped in blankets by grieving relatives. Others still lie in their beds, in doorways, or on the earthen floors of their homes. The survivors are doing everything they can,

to bury their loved ones, but there are too many dead and too few people left alive to dig the graves. When word reached the outside world of the mysterious deaths around Lake Neos, this aid worker was one of the first on the scene. Early reports had suggested that 40 people suffocated in one night, but the aid worker can already tell that those early estimates are horribly inaccurate. More than that have died in this one village alone. Stunned by the scale of the tragedy in Cha, The worker walks on to nearby Nio's village, but nothing he has witnessed so far prepares him for the devastation there. Almost everyone in this village of more than 1,000 people is dead.

Only six men are still alive, and they stand around in a daze of confusion and grief. The aid worker gently questions them and discovers that they only survive through good fortune. They'd been tending cattle on the hillside on the night the mist rolled through when they returned the following morning. not a single person in the village was left alive. The aid worker does what he can to help the weak, dehydrated, and traumatized. Before leaving the village, he stops at the small post office to use the telephone, and in a call to his headquarters, he explains that the situation is far worse than initial reports suggested. Medical teams, food, and clean water are all needed, but more than anything,

they desperately require hundreds of body bags. As the true scale of the catastrophe becomes clear, the remote mountains surrounding Lake Neos are transformed into the center of a huge international relief operation. Convoys of trucks crawl along rough dirt roads carrying doctors, nurses, engineers, and relief supplies. Soldiers establish checkpoints and help evacuate survivors. International aid organizations dispatch medical specialists and disaster experts. And temporary camps are set up for the thousands of thousands of people. villagers who can no longer return to their homes. Eventually, investigators conclude that

more than 1,700 people died in a single night with another 800 left requiring medical treatment. So scientists race to establish the exact cause of these deaths, and their investigations are not simply a matter of scientific curiosity. There are 39 other crater lakes like Nios and Cameroon, unless they can figure out what happened, a similar disaster could occur elsewhere. In March 1987, seven months after the disaster, scientists gather for a conference in the capital of Cameroon. This meeting is dominated by two competing explanations for what happened. One group believes that the dormant volcano underneath Lake Neos briefly reawakened, releasing toxic gases from deep underground. Others suggest a different, rarer kind of eruption, one never seen before by scientists.

According to this theory, carbon dioxide seeped naturally into the low. lake from the magma in the volcano below. Over time, enormous quantities of CO2 accumulated in the lake's deep water. The pressure grew until the gas was suddenly released in what scientists term a limnic eruption, a deadly cloud of carbon dioxide, then rolls silently down into the valleys and villages beneath the lake. Eventually, this limnic eruption theory will be accepted by most scientists. But simply discovering the cause of the Lake Neos disaster will not solve the problem. If carbon dioxide can build silently beneath one crater lake, it can accumulate beneath others as well. So somewhere in the mountains of Cameroon, another disaster may occur unless scientists can find a way

to diffuse these time bombs before they go off. It's March 1995 on Lake Neos, more than eight years after the disaster which claimed nearly 2,000 lives. French scientist Michel Halbach's pushes a raft into the water and watches it float across the deep blue surface. A team of scientists and engineers pulls on ropes to guide the raft into position in the center of the lake. Michel checks the remote control, he holds in his hand, making sure that he's still getting a strong signal from the raft, because this is the moment of truth, the end of an experiment years in the making. On the raft is a device that Michel has been. been working on ever since scientists concluded that the Lake Neos disaster was the result of a

limnic eruption. The machine is relatively simple, just a pipe attached to a pump, but it could save thousands of lives. If all goes to plan, the pipe will be lowered into the depths of Lake Neos, where carbon dioxide is already building up again. But the pump will draw this gas-infused water up through the pipe, allowing the CO2 to disperse into the atmosphere safely. But Michel has to test his invention in the field. An engineer signals that the raft is in position. Using his remote control, Michelle activates the pump, and for a few seconds nothing happens. Michelle begins to worry that the long journey to this moment is about to end in failure.

But then a jet of water suddenly shoots more than 20 yards into the air, casting a rainbow as it sprays back down onto the lake. Michelle allows the pump to run for several minutes, and then comes the crucial test. He turns the pump off, but the water spout doesn't drop. Now that the gas has started escaping, its own pressure keeps the water flowing. The process is effectively self-sustaining. As long as there's carbon dioxide at the bottom of Lake Neos, this machine will remove it from the water. Over the next few hours, Michelle and his team take recordings and make observations,

because this is just a proof of concept. Now they can seek funding for a larger pump that will be installed six, years later in 2001. And with it in place, scientists will be confident that there will be no repeat of the late Nios disaster which killed more than 1,700 people on August 21, 1986. Next on History Daily, August 24, 1572, religious tensions between Catholics and Protestants explode into violence in Paris on St. Bartholomew's Day. From Noisor and Airship, this is History Daily, posted, edited, and executive. produced by me, Lindsay Graham. Audio editing by Mohaminsh Shazi. Sound designed by Molly Bach.

Music by Throne. This episode is written and research by Samuel Hume, edited by Scott Reeves. Managing producer Emily Burr. Executive producers are William Simpson for airship and Pascal Hughes for Noiser.