Information from a poster on Mother Jones:

0-50 rads – No obvious short-term effects
80-120 rads – You have a 10% chance of vomiting and experiencing nausia for a few days
130 -170 rads – You have a 25% chance of vomiting and contracting other symptoms
180-220 rads – You have a 50% chance of vomiting and having other severe physical effects
270-330 rads – 20% chance of death in 6 weeks, or you will recover in a few months.
400-500 rads – 50% chance of death
550-750 rads – Nausea within a few hours ; no survivors
> 1000 rads – immediate incapacitation and death within a week or less.

Japan’s Nuclear Emergency Explained

Could a meltdown in Japan wipe out a large portion of the Western U.S.? It doesn’t seem likely, but I know nothing about nuclear power.