No radiation levels of concern have reached the United States from Japan

WASHINGTON — The U.S. government has an extensive network of radiation monitors around the country and no radiation levels of concern have been detected from the nuclear reactor emissions in Japan.

The U.S. Environmental Protection Agency RadNet system is designed to protect the public by notifying scientists, in near real time, of elevated levels of radiation so they can determine whether protective action is required. The EPA’s system has not detected any radiation levels of concern.

In addition to EPA’s RadNet system, the U.S. Department of Energy has radiation monitoring equipment at research facilities around the country, which have also not detected any radiation levels of concern.

As part of the Comprehensive Nuclear Test Ban Treaty Organization’s International Monitoring System (IMS), the Department of Energy also maintains the capability to detect tiny quantities of radioisotopes that might indicate an underground nuclear test on the other side of the world. These detectors are extremely sensitive and can detect minute amounts of radioactive materials.

Minuscule isotopes

One of the monitoring stations in Sacramento, Calif., that feeds into the IMS has detected minuscule quantities of iodine isotopes and other radioactive particles that pose no health concern at the detected levels. Collectively, these levels amount to a level of approximately 0.0002 disintegrations per second per cubic meter of air (0.2 mBq/m3).

Similarly, between March 16 and 17, a detector at the Department of Energy’s Pacific Northwest National Laboratory in Washington State detected trace amounts of Xenon-133, which is a radioactive noble gas produced during nuclear fission that poses no concern at the detected level.

No concern

The levels detected were approximately 0.1 disintegrations per second per cubic meter of air (100 mBq/m3), 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.

These types of readings remain consistent with our expectations since the onset of this tragedy, and are to be expected in the coming days.

Chernobyl

Following the explosion of the Chernobyl plant in Ukraine in 1986 — the worst nuclear accident in world history — air monitoring in the United States also picked up trace amounts of radioactive particles, less than one thousandth of the estimated annual dose from natural sources for a typical person.