Scientists are warning that another disaster is possible at a lake in Cameroon that suddenly released huge amounts of carbon dioxide in 1986, killing 1,700 people, as well as cattle, birds and other animals.
The deadly gas came from the bottom of Lake Nyos, and an international team has concluded that about 300 million cubic meters of the gas have again accumulated under the lake, making it "very dangerous" to those who have resettled there.
The group estimated that 3 million cubic meters were being added annually, a meter being slightly longer than a yard.
The gas is assumed to be of volcanic origin, accumulating in water at the bottom of the lake until turbulence or some other factor releases it. The lake is in a volcanic region of Cameroon, in western Africa.
"Another gas disaster could occur at any time, "so the carbon dioxide in Lake Nyos should be reduced as a
matter of urgency," the group reported in a recent letter to the journal Nature.
It suggested that gas-laden water be pumped from the bottom of the lake through a series of pipes.
It warned, however, that the rate of removal should not exceed inflow, lest the lake level be lowered, reducing pressure on the bottom that confines the heavy, gaseous water there. The removed water should be discharged outside the surrounding valley, it said.
It also recommended that the method first be tested on Lake Monous, 60 miles to the southeast, where 37 people were killed by a similar disaster in 1984.
That lake is only half as deep as Lake Nyos and "potentially far less dangerous," the group said. During the degassing, the scientists added, preparations should be made for a medical emergency, in case something goes wrong.
The chairman of the group was S. J. Freeth of the University of Swansea in England.