Thyroid abnormalities have shown up in American babies living along the West Coast, which researchers say was caused by radiation that leaked from Japan’s Fukushima Daiichi nuclear power plant in 2011.

Babies born in California, Alaska, Hawaii, Oregon and Washington between one week and 16 weeks after the nuclear meltdown began in March 2011 were found to be 28% more likely to suffer from congenital hypothyroidism (CH) than children born in those states during the same period one year earlier.

The results come from a new study (pdf) conducted by researchers at the Radiation and Public Health Project. The findings were published by the Open Journal of Pediatrics.

According to researchers, “Fukushima fallout appeared to affect all areas of the US, and was especially large in some, mostly in the western part of the nation.” Their report measured incidence of CH and contamination levels of radioactive iodine isotopes (I-131).

In California, a team from California State University, Long Beach found high levels of I-131 in kelp along the coast. Orange County had 250 times as much I-131 as it did before the Fukushima accident. Santa Cruz levels were 200 times as high and Los Angeles County, 60.

The researchers also analyzed data from the U.S. Environmental Protection Agency (EPA) that indicated airborne levels of a variety of radioactive isotopes for 18 West Coast sites were 7.345 times normal. Eureka was 38.264, Anaheim 14.941 and San Bernardino 12.054. The airborne levels were viewed by the researchers as a proxy for relative thyroid gland exposures.

CH occurs as a result of radioactive iodine building up in thyroids. The condition can cause stunted growth, lowered intelligence, deafness, and neurological abnormalities.

More than 40% of the Japanese children studied in the aftermath of the Fukushima disaster exhibited evidence of thyroid abnormalities. Harvey Wasserman, founder of nukefree.org, called it an indication of a "horrifying plague."

The new report’s conclusions “suggest that Americans may have been harmed by Fukushima fallout,” said one of the project’s researchers, Joseph Mangano. “Studies, especially of the youngest, must proceed immediately."

–Noel Brinkerhoff, Danny Biederman

To Learn More:

Fukushima Meltdown Driving Increased Abnormalities Among US Infants (by Lauren McCauley, Common Dreams)

Elevated Airborne Beta Levels in Pacific/West Coast US States and Trends in Hypothyroidism among Newborns after the Fukushima Nuclear Meltdown (by Joseph J. Mangano and Janette D. Sherman, Open Journal of Pediatrics) (pdf)

Fukushima's Fallout Is Already Harming Our Children (by Harvey Wasserman, Free Press)

Fukushima Radioactive Fallout Much Worse than Previously Reported (by Noel Brinkerhoff and David Wallechinsky, AllGov)

Japanese Radiation Arrives at U.S. Airports (by Noel Brinkerhoff, AllGov)