"The NRC [U.S. Nuclear Regulatory Commission] continues to see public interest in low concentrations of radioactive material detected off the U.S. West Coast. The material comes from the Fukushima Daiichi Nuclear Power Station's catastrophic and unprecedented accident following the Great Japan Earthquake and Tsunami of March 2011. While the NRC has created this background discussion, more up to date information is available through the links (such as to Japan's Nuclear Regulatory Authority (JNRA)) at the end of this report. While the NRC continues to examine information on this situation, many other Federal and State agencies carry out the environmental monitoring needed to determine any health and safety effects from the Fukushima-based contamination. […] The available evidence continues to lead the NRC and other Federal, State and local governments to conclude the low levels of radiation leaking into the ocean from Fukushima Daiichi fall well short of posing any U.S. health or environmental risk."
U.S. Nuclear Regulatory Commission: http://www.nrc.gov/