I was thinking something more along the line of Lake Nyos in Africe, where some event causes a massive CO2 cloud to be released, smothering thousands of people.
That's bad, too. The entire concept of capturing CO2 as a gas and somehow storing it indefinitely is so patently absurd that it defies all logic. To think someone so stupid that he thinks he can make money off of this as Chu does, ran the Obama scientific community, is hard to comprehend.