I saw this article while reading NPR news on my phone the other day.
Out in the Dakotas there is a formation called the Bakken shale, which contains a lot of oil and gas that has recently become economically recoverable due to hydrofracking technology. Basically they are flaring off (burning) huge amounts of cheap natural gas to get at the oil, which is a much more lucrative product on the open market. Sustainable????
And industry has apparently promised to do better, see this NYT article
It sounds more sustainable than before. Rather than just burning up natural gas, it is now being used. They are now putting up pipe line to reuse waste natural gas.