So far, so good. Sounds like the U.S. won't have any imminent danger from Japan's nuclear accident:

WASHINGTON–U.S. officials detected the presence of a radioactive isotope in California on Friday that appeared to come from the Fukushima nuclear-power plant in Japan, but the levels they detected were minuscule–far less than a person would normally receive from the sun, rocks or other natural sources.

U.S. officials say the levels are consistent with their expectations and pose no risk to human health.

The Environmental Protection Agency and the Energy Department said in a statement a radiation monitor in Sacramento, Calif., detected minuscule quantities of the radioactive isotope xenon-133. The readings validated similar ones from March 16 and 17 taken from monitors in Washington state, they said.

The agencies said the radioactive isotope appears to have come from the Japanese power plant damaged in the wake of the earthquake and tsunami there. Energy Secretary Steven Chu said earlier in the week he believed a “partial meltdown” had occurred at the plant..