<P> On 21 August 1986, a limnic eruption at Lake Nyos in northwestern Cameroon killed 1,746 people and 3,500 livestock . </P> <P> The eruption triggered the sudden release of about 100,000--300,000 tons (1.6 m tons, according to some sources) of carbon dioxide (CO). The gas cloud initially rose at nearly 100 kilometres per hour (62 mph) and then, being heavier than air, descended onto nearby villages, displacing all the air and suffocating people and livestock within 25 kilometres (16 mi) of the lake . </P>

How many animals died in the lake nyos tragedy