Lake Nyos, Cameroon, was the site of an horrific gas eruption in 1986. Fumes from the underground volcano suffocated more than a thousand local residents and devastated the livestock industry.

Photo by Jack Lockwood, USGS

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  • On August 21, 1986, a cloud of toxic gas erupted from Lake Nyos, Cameroon. Lake Nyos is a lake that developed in the crater of an inactive volcano. Lake Nyos absorbs carbon dioxide that sometimes leaks from the volcano below. In 1986, this dissolved carbon dioxide erupted from Lake Nyos, a natural hazard called a limnic eruption. The toxic gas spilled over the crater's rim and flowed into villages in the valley surrounding the volcano. About 1,700 people and 3,500 livestock suffocated after breathing the deadly gas.

    Following the Lake Nyos disaster, scientists put large pipes in the lake, leading from the lake bottom to above the surface. The pipes allow carbon dioxide to escape as soon as the volcano releases it. The small amount of gas, piped out continuously over time, is not enough to be dangerous.

  • Term Part of Speech Definition Encyclopedic Entry
    carbon dioxide Noun

    greenhouse gas produced by animals during respiration and used by plants during photosynthesis. Carbon dioxide is also the byproduct of burning fossil fuels.

    cloud Noun

    visible mass of tiny water droplets or ice crystals in Earth's atmosphere.

    Encyclopedic Entry: cloud
    crater Noun

    bowl-shaped depression formed by a volcanic eruption or impact of a meteorite.

    Encyclopedic Entry: crater
    disaster Noun

    terrible and damaging event.

    erupt Verb

    to explode or suddenly eject material.

    gas Noun

    state of matter with no fixed shape that will fill any container uniformly. Gas molecules are in constant, random motion.

    lake Noun

    body of water surrounded by land.

    Encyclopedic Entry: lake
    livestock noun, plural noun

    animals raised for sale and profit.

    toxic Adjective


    valley Noun

    depression in the Earth between hills.

    volcano Noun

    an opening in the Earth's crust, through which lava, ash, and gases erupt, and also the cone built by eruptions.

    Encyclopedic Entry: Plate Tectonics and Volcanic Activity