Carbon dioxide gas erupts from <a href="https://en.wikipedia.org/wiki/Volcano" id="mwAUI" rel="mw:WikiLink" title="Volcano">volcanic</a> <a href="https://en.wikipedia.org/wiki/Lake_Nyos" id="mwAUM" rel="mw:WikiLink" title="Lake Nyos">Lake Nyos</a> in <a href="https://en.wikipedia.org/wiki/Cameroon" id="mwAUQ" rel="mw:WikiLink" title="Cameroon">Cameroon</a>, killing up to 1,800 people within a <span about="#mwt78" data-mw='{"parts":[{"template":{"target":{"wt":"convert","href":"./Template:Convert"},"params":{"1":{"wt":"20"},"2":{"wt":"km"},"adj":{"wt":"on"}},"i":0}}]}' id="mwAUU" typeof="mw:Transclusion">20-kilometre (12</span><span about="#mwt78" typeof="mw:Entity"> </span><span about="#mwt78">mi)</span> range.