US nuclear gas experiment produced 213m cubic feet, but gas was radioactive
In 1967, the US detonated a 29-kiloton nuclear device 4,227 feet underground in New Mexico to boost natural gas production. Five tests produced 213 million cubic feet of gas, but it contained measurable radioactivity. The experiment was later ended, the site cleaned up, and radioactive contamination remains underground in the blast zone.
We haven't written up this one. Times of India has the full story — the link below goes straight to it.
