In 1986, possibly as the result of a landslide, Lake Nyos suddenly emitted a large cloud of CO2, which suffocated 1,746 people[3] and 3,500 livestock in nearby towns and villages, the most notable one being Chah, which was abandoned after the incident.

[4][5] The limnic eruption not only devastated human and livestock populations but also had a profound impact on the diverse aquatic life, including tilapia, crabs, snails, and frogs, leading to a significant loss of biodiversity in and around the lake.

To prevent a recurrence, a degassing tube that siphons water from the bottom layers to the top, allowing the carbon dioxide to leak in safe quantities, was installed in 2001.

[7] Lake Nyos fills a roughly circular maar in the Oku Volcanic Field, an explosion crater caused when a lava flow interacted violently with groundwater.

But with advanced in technology now there are machinery placed at the bottom of the lake to remove the gases, so as to make the inhabitants of the area free from danger.

Over long periods, carbon dioxide gas seeping into the cold water at the lake's bottom is dissolved in great amounts.

However, on August 21, 1986, a limnic eruption occurred at Lake Nyos, triggering the sudden release of about 100,000–300,000 tons[11] (some sources state as much as 1.6 million tonnes)[12] of CO2.

This gas cloud rose at nearly 100 kilometres per hour (62 mph) and[6] spilled over the northern lip of the lake into a valley running roughly east–west from Cha to Subum.

It then rushed down two valleys branching off to the north, displacing all of the air and suffocating 1,746 people within 25 kilometres (16 mi) of the lake, mostly rural villagers, as well as 3,500 livestock.

Whatever the cause, the event resulted in the rapid mixing of the supersaturated deep water with the upper layers of the lake, where the reduced pressure allowed the stored CO2 to effervesce out of solution.

These use a pump to initially lift water from the bottom of the lake, heavily saturated with CO2, until the loss of pressure begins releasing the gas from the diphasic fluid, at which point the process becomes self-powered.

In 2005, Isaac Njilah, a geologist at the University of Yaoundé, suggested that the natural dam of volcanic rock that keeps in the lake's waters could collapse in the near future.

The Cameroonian government, speaking through Gregory Tanyi-Leke of the Institute of Mining and Geological Research, acknowledges the weakening wall, but denies that it presents any immediate threat.

A United Nations team led by Olaf Van Duin and Nisa Nurmohamed of the Netherlands' Ministry of Transport and Public Works inspected the dam over three days in September 2005, and confirmed that the natural lip had weakened.