Japanese government orders release of radioactive vapor to relieve rising pressure in nuclear reactor:
Chief Cabinet Secretary Yukio Edano said the amount of radioactive element in the vapor would be "very small" and would not affect the environment or human health. Ref. Source 4
Possible Worker Injuries, Shaking, Smoke Reported at Japanese Nuclear Plant Facing Possible Meltdown [3:32 a.m.] Ref. ABC News
We are assuming that a meltdown has occurred" at a quake-damaged nuclear reactor, Japan's chief Cabinet secretary says. Ref. CNN
Japan Nuclear Disaster
U.N. Agency: State of emergency at nuclear power plant in Onagawa, Japan, where excessive radiation levels reported. Ref. CNN
If a meltdown has or is occurring this could be be bad for the local area and for the world as the nuclear vapor travels the globe on the prevailing winds. Especially the jet stream that passes over that area.
The number of nuclear plants damaged in Japan is so bad that I will have to rename this thread to cater for all of them: