I thought the French had built a facility that was slowly venting off the gas at the bottom.
Sorry I am late but is was out of town.
Regs to that lake. It is supposed to have the largest collection of CO2 and Methane in Africa at the bottom. They claimed that if that volcano ever managed to get lava into that lake they feared it would overturn...like a couple of smaller lakes that did that and resulted in a huge die off around the lakes. It took them some time to figure out what the heck happened to those populations around those lakes until some medical experts looked at the bodies and all that.
But you are right, they are siphoning gas off the lake commercially, but it isnt but a small amount to the amount on the bottom. .