Massive Carbon Dioxide Release Kills Thousands at Lake Nyos

Summary

Lake Nyos, a volcanic crater lake in northwestern Cameroon, had long accumulated dissolved carbon dioxide from underlying magma. On the evening of August 21, 1986, a limnic eruption triggered the sudden release of a massive cloud of CO2 gas. The denser-than-air cloud flowed down valleys, asphyxiating people and livestock in nearby villages. Approximately 1,746 people and 3,500 animals died within hours, primarily from oxygen deprivation. Survivors reported a smell of rotten eggs and a rumbling sound before the disaster struck. International teams later investigated the rare geological event.

Why It Matters

The Lake Nyos disaster revealed the dangers of gas-charged lakes in volcanic regions and prompted global scientific monitoring programs. It led to engineering solutions like degassing pipes installed at Nyos and similar lakes to prevent future catastrophes.

Related Portfolio Site

Disaster Kit Pro: Natural disaster history of the Lake Nyos limnic eruption

Sources

1. Lake Nyos disaster, Wikipedia. Accessed 2026-07-02.
2. Lake Nyos disaster (1986), Encyclopædia Britannica. Accessed 2026-07-02.