Lake Nyos, or to be more precise, the upper 38 m of Lake Nyos, is held back by a natural dam (Figure 1) which, if it were to fail, would wreak havoc in the valleys to the north and cause a serious flood to surge down the Katsina Ala into Nigeria. Lockwood et al., , who have been investigating the Lake Nyos gas disaster, which killed an estimated 1700 people in August 1986, presented a paper on the potential for disastrous failure of the Lake Nyos dam to the AGU Fall Meeting. Part of what they said was subsequently reported in New Scientist (December 10, 1987, p. 18). They have placed on record their view that the dam is only 400 years old and are reported to have stated that it is eroding away at the alarming rate of 1.5 m/yr. If their figures are correct, then surely the dam will fail within a decade or two at the most, and there is indeed cause for alarm and immediate action. However, teams from Cameroon, France, Italy, Japan , Switzerland, Britain, Nigeria, and Germany also visited Lake Nyos in the immediate aftermath of the gas disaster, and none of their reports have suggested that the dam is in itself an imminent threat.