My wife and two sons are flying to Los Angeles tomorrow but I'm not worried about the so-called "radioactive plume" coming from the crippled Japanese nuclear reactors. In fact, I hate the term "radioactive plume" - now appearing widely in the media - because it conjures up an image that is much scarier than the reality of the radiation danger to the West Coast.
Earlier today, as concerned residents in California and Washington awaited further news about the plume, the Associated Press reported that a diplomat with access to radiation tracking by the U.N.'s Comprehensive Test Ban Treaty Organization said tiny amounts of radiation had reached California.
But as radiation expert Dr. Donald Bucklin told me today, these instruments "can measure miniscule changes in radiation" that have "absolutely no effect on human beings." In fact, according to the diplomat, initial readings were not dangerous in any way -- "about a billion times beneath levels that would be health threatening."
Despite reassurances from many different experts and agencies, fear - much more than radioactivity - was in the air: tweeted, emailed, and broadcast. A physician friend in L.A. emailed me that there was widespread panic among his patients and asked me to go on CBS radio - which I did - to try to provide a reality check. After consulting with experts on radiation and nuclear accidents over the past several days, here's why I'm not worried:
1) Chernobyl was a much worse accident yet no significant radiation reached the U.S.
CBS News nuclear safety consultant Cham Dallas, a PhD in toxicology who spent ten years studying the impact of the Chernobyl accident, told me that the radiation released at the Russian reactor was 100 times more than the combined radiation from Hiroshima and Nagasaki. But only an insignificant "blip" of radiation reached Savannah, Georgia about 5400 miles away - about the same distance as Tokyo is to Los Angeles. And no health problems in the U.S. have been detected as a result of Chernobyl, which was a level 7 incident according to The International Atomic Energy Agency; the crisis in Japan is currently level 5.
2) Experts tell me the amount of radiation released from the Japanese nuclear reactors is not nearly enough to cause a problem in the U.S.
Radiation dose is measured in something called "millisieverts." Background dose due to natural radiation exposure varies from place to place but is about 3 millisieverts a year. Nuclear plant workers are limited to 20 millisieverts a year. One hundred millisieverts in one dose can increase the risk of cancer. One hundred to 500 millisieverts can cause bone marrow damage, leading to infection and death. A chest x-ray is 0.1 millisieverts.
The Tokyo Metropolitan Government announced today that radiation levels in downtown Tokyo were at 0.000047 millisieverts an hour, barely higher than the 0.000035 millisieverts an hour that is typical.
Cham Dallas told me today that - as it stands now - any cumulative radiation exposure to people on the West Coast as a result of the Japanese accident should be clinically insignificant, amounting to less than a tenth of a chest x-ray (0.01 millisieverts).
3) Direct measurements of radiation on the West Coast reveal no significant increase so far.
This afternoon, health officials in California and Washington said radiation is not higher than usual. Tonight, the Environmental Protection Agency confirmed that no radiation levels of concern have reached the United States, saying: "The doses received by people per day from natural sources of radiation - such as rocks, bricks, the sun and other background sources - are 100,000 times the dose rates from the particles and gas detected in California or Washington State."
On the West Coast, pharmacies are being cleaned out of potassium iodide pills by people wanting to protect themselves from thyroid cancer caused by radioactive I-131. Today the CDC tweeted not to take potassium pills. Tonight I received an email from a patient in Los Angeles asking me if she should stockpile potassium iodide. The answer is a definitive "absolutely not." And under no conditions should anybody take iodide pills or other forms of iodine without being told to do so by a health professional; the side effects can be very serious.
Obviously, in Japan the situation is quite different from here in the United States. The leak of radioactivity may well have health effects on those workers who have been directly exposed at the plants. Experts will need to monitor the residents in other areas of Japan for signs of radiation-associated illness. And officials in Japan will be looking for evidence of radioactivity entering the food chain. In the United States, imported food is routinely checked for radioactivity.
As for my family, I will send them off to Los Angeles tomorrow with my usual reluctance. But I will not have a millisievert of fear about radioactivity.
Dr. Jonathan LaPook, M.D. is the medical correspondent for the CBS Evening News.