In the months following the 2011 meltdowns at Japan’s Fukushima Daiichi nuclear power plant, residents of Los Angeles were being exposed to levels of dangerous alpha radiation nearly 1,000 times above normal levels, a government study found.
The data came from a July 2012 presentation at the National Conference on Radiation Control. The presentation was given by Joji Ortego, Principal Radiation Protection Specialist for Los Angeles County Radiation Management.
Following the Fukushima meltdowns, Los Angeles county heard many concerns from residents about the potential health impacts of radiation crossing the Pacific Ocean from the disaster. So they commissioned a study of radiation levels in the area. The report notes that federal agencies delayed in providing information to the county, and that the state Radiologic Health Branch was unable to provide inspectors due to budget constraints. The state lab was unable to provide a reasonable turnaround time for sample analysis, so the county instead hired a local radiation monitor manufacturer for the analysis.
Radiation levels exceed federal thresholds
Samples were taken between April 29 and May 2, 2011, approximately seven weeks after the radioactive releases from Fukushima. The county found that gross alpha radiation levels at a location in Los Angeles were 300 femtocuries per cubic meter (fCi/m3), and levels at a Hacienda Heights location were 200 fCi/m3.
For context, the Lawrence Livermore National Laboratory reports the average (annual median) level of gross alpha activity for the state of California as just 0.38 fCi/m3 – that is, 790 times lower.
The levels detected in Los Angeles County were a full 100 times higher than the level that requires an investigation at a U.S. nuclear laboratory, according to the Environmental Monitoring Plan at Brookhaven National Laboratory: “If the gross alpha activity in the [air] filters is greater than 3 fCi/m3, then collect more samples in the vicinity, and project manager will review all detections above the limits … All values greater than the above-stated gross alpha/beta concentration shall trigger an investigation.”
Finally, the Los Angeles County levels were almost 15 times higher than the federal regulatory limit for alpha radiation, which is 21 fCi/m3, according to a 2010 document from Idaho National Laboratory.