There’s growing alarm worldwide about radiation poisoning, with an explosion Monday morning at the No. 3 reactor of the Fukushima Daiichi nuclear complex. A similar blast at the No. 1 reactor in the same complex released radiation into the environment on Saturday, and while officials in Japan and the World Health Organization have since described the public health risk as “quite low,” concern about the potential of serious health problems abound.
Officials in the U.S. and U.K. have released statements assuring the public that there is no imminent radiation threat in these countries. Philippine authorities have had to quash a text hoax that caused some offices and classes to shut down after it warned of thyroid health issues and the dangers of stepping outdoors without a raincoat.
Following are quick facts on radiation exposure and its possible health consequences.
Who is at highest risk of radiation poisoning?
The nearly 200 Japanese people who have been taken to the hospital with suspected radiation exposure and those who were living within roughly 12 miles of the Fukushima nuclear power plant (and have been asked to evacuate) are presumably at higher risk than others. Other risk groups, according to CBS News, include the cleanup workers who have been exposed to the radiation in the nuclear facilities as well as children under 18 and fetuses in the womb — they have the most actively dividing cells in their bodies.
The New York Daily News also reports:
Seventeen U.S. Navy crew members have been contaminated with low-levels of radiation during disaster relief missions in Japan, military officials said Monday.
The radioactivity was detected when the service members returned to the aircraft carrier Ronald Reagan aboard three helicopters. They were treated with soap and water and their clothes were discarded.
“No further contamination was detected,” the military said.
TIME’s Ecocentric blog reports here on the types of radioactive isotopes that were likely to have been emitted by the crippled Fukushima reactors, and what the risks may be to those exposed.
So far, however, the immediate health risks of radiation appear minimal, and levels outside the plant have remained at safe levels.
Why did the Japanese government hand out potassium iodide pills?
After a nuclear event, radioactive iodine may be released into the air and the iodine pills were likely given out to protect those who may be exposed. According to the Centers for Disease Control and Prevention (CDC), potassium iodide prevents the thyroid gland from quickly absorbing radioactive iodine if inhaled.
However, as the New York Times explains:
Dr. [David J.] Brenner said the iodine pills were protective, but were “a bit of a myth” because their use is based on the belief that the risk is from inhaling radioactive iodine. Actually, he said, 98 percent of people’s exposure comes from milk and other dairy products.
“The way radioactive iodine gets into human beings is an indirect route,” he said. “It falls to the ground, cows eat it and make milk with radioactive iodine, and you get it from drinking the milk. You get very little from inhaling it. The way to prevent it is just to stop people from drinking the milk.” He said that the epidemic of thyroid cancer around Chernobyl could have been prevented if the government had immediately stopped people from drinking milk.
Crops can also be contaminated. “I wouldn’t be eating an apple from a tree close to the plant,” Dr. Brenner said.
What is the overall risk of radiation exposure from contaminated food?
In this case, there should be no cause for concern given the reported radiation levels, according to Bloomberg.com. Still, officials in South Korea, Hong Kong, Singapore and the Philippines will reportedly be checking food imported from Japan for possible signs of radiation to ensure their safety for consumption.
Is there risk for cancer?
When thyroid cells absorb too much radioactive iodine — either through the air or through contaminated food — it can increase the risk for thyroid cancer, says the American Thyroid Association. Babies and young children are at highest risk as their thyroid glands are most radiation-sensitive. People over 40 are at less risk.
The massive explosion at Chernobyl in 1986 caused an epidemic of thyroid cancer and increases in leukemia rates. By comparison, the partial core meltdown at Three Mile Island in 1979, which released about one million times less radiation, according to the New York Times, did not appear to impact cancer rates even decades later.
The radiation release in Japan appears to be much closer to that of the Three Mile Island incident than Chernobyl.
What is acute radiation syndrome, and what are its initial symptoms?
Exposure to high levels of radiation can cause acute radiation syndrome (ARS), or radiation poisoning. The first symptoms of ARS are typically nausea, vomiting and diarrhea. These symptoms, the CDC says, start within minutes to days after the exposure, and can last for minutes or days. A person with ARS can look and feel healthy, then get sick again later. Later symptoms, which may last hours or months, include loss of appetite, fatigue, fever, nausea, vomiting, diarrhea and possibly even seizures, coma and death. Radiation poisoning also usually causes skin damage.