The health hazards of radiation

Workers scrambling to prevent nuclear meltdown at Japan’s crippled Dai-ichi nuclear plant are being heralded as heroes. It is unknown exactly what levels of radiation they have encountered, but even under the best-case scenario, they face serious risks.

Evelyn Talbott, professor of epidemiology at the University of Pittsburgh, said workers can protect themselves against one type of radiation by wearing anti-contamination suits. That protects from “beta” radiation, which happens when radioactive dust or particles land on the skin.

“But the X-ray, the gamma radiation, the stuff that requires a lead 3-foot shield,” Talbott said. “They’re not protected from that at all.”

Both types of radiation have the same effect. What matters is how much radiation workers encounter; that information has not been released by Japanese authorities.

At relatively low levels of exposure, cancer risks are elevated. At much higher levels, like such as those that occur during complete nuclear meltdown, bone marrow cells begin dying. When that happens, white blood cells, which run our immune systems, stop production, explained Richard Vetter, emeritus radiation safety officer and biophysics professor at the Mayo Clinic.

“If someone received an acute dose in a very short period of time, they would get very sick,” Vetter said. “They would be at very high risk of infection because their white blood cells would decrease dramatically.”

Production of red blood cells slows, which decreases the oxygen delivered to the body, and the lining of the intestines also starts to deteriorate.

These symptoms, part of Acute Radiation Syndrome, or ARS, occur when exposure levels hit about 1,000 millisieverts in an hour. That is more than double the highest rates reported by the International Atomic Energy Agency so far.

According to a recent U.N. report, 28 emergency workers died of ARS in the months following the Chernobyl disaster, which experts say was much worse than the catastrophe in Japan.