Tuesday's explosion at the No. 2 reactor in the Fukushima complex, 150 miles north of Tokyo, for the first time raised the possibility that the key containment structure of the unit, which protects the reactor vessel and keeps dangerous radioactive materials from leaking out, had been damaged.

WSJ: Japan's Nuclear Crisis Escalates

Rather, as a consequence of injecting water and sand into the shale formation to crack the rocks so gas and oil will flow, massive amounts of waste water comes back to the surface with significant amounts of contaminants as a result of leaching out salt, heavy metals and trace amounts of radioactive materials from the rock formation itself.

FORBES: U.S. Energy Independence - So Close, Yet So Far

Just to be clear, what we sent out were these pods, and these pods measure deposition of radioactive materials on the ground.

WHITEHOUSE: Press Briefing