A second reactor unit at the Fukushima Daiichi nuclear plant in Japan may have ruptured, authorities announced on Wednesday. This is on top of their earlier revelation that the containment vessel of a separate reactor unit had cracked.

As of Tuesday, four nuclear reactors in Japan seem to be in partial meltdown in the wake of an earthquake and tsunami, according to Christian Parenti of the Nation:

Two disasters flared up this week, one environmental, the other political. Off the coast of Louisiana, oil from a sunken rig is leaking as much as five times faster than scientists originally judged, and the spill reportedly reached land last night. And in Washington, Sen. Lindsey Graham (R-SC) jumped from his partnership with Sens. John Kerry (D-MA) and Joe Lieberman (I-CT) just before the scheduled release of the draft of a new Senate climate bill.

The trio had worked for months on bipartisan legislation on climate change. After Graham’s defection, his partners promised to press on, but the bill’s chances of survival are dimmer.

The next Exxon Valdez?