Report on Gamma-Ray Analysis of Seaweed Samples from Naturespirit Herbs   LLC
  Five seaweed samples from Naturespirit Herbs LLC were counted using low-background high-resolution gamma-ray detectors to search for evidence of contamination from the Fukushima reactor accident. No evidence of Cs-134 was observed in any of the samples. Very low levels of Cs-137 were observed and are attributed to fallout from atmospheric nuclear weapons testing. However, these levels of Cs-137 are small compared to the levels of the naturally occurring K-40 observed from these seaweed samples. 
Eric B. Norman, Keenan Thomas, Pedro Guillaumon, Alan R. Smith
nucl-ex physics.ins-det