Youngstown earthquakes raise issues on oilfield wastes from shale exploration

Out-of-state oilfield fluid waste accounts for nearly 2 million barrels a quarter, which was roughly 57 percent of the total waste dumped into the ground during the third quarter of 2010, according to the Ohio Department of Natural Resources.

http://www.cleveland.com/open/index.ssf/2012/01/earthquake_raises_issues_on_oi.html