The Boston Marathon attack has drawn new attention to the risk of radiation poisoning from a dirty bomb detonated in a heavily-populated urban area. Bostonians were inconvenienced by the shutting down of their city for a day; imagine if it had been a dirty bomb and a quarter million people had been ordered to evacuate their homes and offices, because of false fears about the amount of radiation which is actually dangerous.

A recent New York Times report, “U.S. Rethinks How to Respond to Nuclear Disaster,” offers a helpful reminder that the greatest threat from terrorism is often what Washington does in response, such as launching unnecessary foreign wars or clamping down on civil liberties. Every crisis can become an excuse for Congress to loot the American treasury, impose new taxes, and grow the power and intrusiveness of government. Nuclear radiation, fanned by media-generated panic and ignorance, is always at the top of the list of most feared events and is therefore an area particularly open to government overreaction.  

After the 2011 Fukushima nuclear accident, Japan, following conventional guidelines, evacuated 160,000 persons from their homes, based on exposure levels of 2 REM (a REM is the unit of measure used to gauge radiation damage to human tissue). Yet not a single person died and hardly any got ill, even among the emergency nuclear workers at the reactor.

Actual radiation sickness begins at exposure of 100 REM, some 50 times the risk used to evacuate Japanese civilians. However even this risk can be minimized by staying indoors and closing windows. Later the Japanese government raised the limit for responders to 250 millisieverts (25 REM) from the initial 100 millisieverts (10 REM) which was inhibiting emergency response.

This excessive caution all comes from old U.S. limits of 15 millirem (.015 REM) which was considered the threat level of radiation for humans. For perspective consider that the average American is exposed to 360 millirems (.360 REM) per year while pilots and residents of high cities, such as Denver, get .920 REM. A Scientific American article explained how Japanese authorities ordered evacuation of anybody living within 20 kilometers of the stricken plant and told those within 30 kilometers to take shelter and stay indoors. It also reported that the U.S. Nuclear Regulatory Commission then recommended that any American within 80 kilometers evacuate the area. That’s the kind of panic response we might expect here in America if we get hit with a dirty bomb.

My 2005 article “Radiation Limits, Dirty Bombs and Chaos” described much about nuclear radiation dangers, how to protect oneself, and about the wrong advice given by government agencies. Even today, Washington shies away from declaring what amount of radiation is dangerous. FEMA (Federal Emergency Management Administration) removed its initial post-9/11 instructions to just run away from any radiation. That was the old ALARA (As Little Radiation As Possible) FEMA rule. However, even today I can’t find any specifics on the FEMA website about what level of radiation starts to be dangerous. Also, one can spend hours on the Homeland Security website looking in vain for similar information.

Recent hearings by the House Homeland Security Subcommittee focused on the possibility of the Boston bombing attack having been a radiological one. Yet those hearings featured no discussion of different radiation danger thresholds, while New York’s Police Commissioner for Counter Terrorism described the threat as if they still used the 15 millirem limit. He said that the consequence of a dirty bomb the size of the devices used in Boston would contaminate a large part of the city, devastating its economic life with major evacuations of population.  

In March the EPA posted new, much higher potential guidelines for commentary and environmentalists promptly attacked them. But in fact those environmentalists may simply fear that a realistic radiation threat analysis could start unwinding much of their general activism against the use of nuclear power. While the EPA website now shows that health risks begin at 50 REM, it still uses the old, lower numbers for its threat warnings. For example, EPA still uses the 15 millirem limits for other issues, such as for residents in the vicinity of the Yucca Mountain waste storage site in Nevada. Also EPA still uses the 15 millirem limits for superfund cleanups, thus adding hundreds of millions, if not billions, of dollars to the costs of such work. 50 REM is 3,500 times 15 millirem (.015) and even 50 is lower than the 100 REM threshold commonly used for radiation sickness. That would be 7,000 times as high.

Initially, the old EPA limit may have been supposed to help ward off the threat of cancer. But these limits came into effect after World War 2 when scientists knew little about radiation’s threat to human beings. Today, however, there is a vast body of evidence showing that low doses of radiation, up to 10 REM, build resistance to many diseases and prolong human life. After Hiroshima, victims not killed actually lived longer than average life spans.

The EPA’s long reliance on these levels weakens America’s civil defense. Many EPA critics believe it is due to the agency not wanting to provoke criticism by extreme environmentalists, who appear to oppose almost any measures that would lessen public worry about “nukes.” Many environmentalists do indeed stoke fears in order to prevent the establishment of new nuclear electric energy plants and to promote universal nuclear disarmament. In response to the EPA’s March announcement, for instance, one leading environmentalist website immediately attacked the agency and came out against any modification to the government’s radiation rules. So far, this fear-mongering seems to be paying off. As The New York Times story cited above notes, Washington has so far failed to adjust its radiation danger thresholds.

The exaggerated threats from the Environmental Protection Agency guidelines are further exacerbated by the pervasive theory of Linear No-Threshold Dose Hypothesis (LNT), which extrapolates statistics to infinite, and frequently idiotic, extremes. For example, LNT deducts that, if falling 100 feet onto concrete is invariably fatal, then out of 10,000 people falling one inch, 10 of them will die from the fall. Or if 100 aspirin is a fatal does, then out of 100 people each taking one aspirin, one of them will die. By such reasoning any tiny amount of radiation will kill some number of people out of every million exposed. LNT is how the government came up with many of its dubious risk guidelines for chemicals and minerals—all while scientific research has progressed to the point where we can actually measure parts per billion, thus creating fear that almost any product may be dangerous.   

Forbes magazine recently explained how LNT does not take the immune system into account:

The linear no-threshold dose hypothesis (LNT) does not apply to doses less than 10 rem, (note Japan’s evacuation above 2 Rem, Ed) which is the region encompassing background levels around the world, and is the region of most importance to nuclear energy, most medical procedures and most areas affected by accidents………– radiation doses less than about 10 rem (0.1 Sv) are no big deal.  LNT does not apply to doses less than 10 rem    

To recap, LNT is a supposition that all radiation is deadly and there is no dose below which harmful effects will not occur. Double the dose, double the cancers. First put forward after WWII by Hermann Muller, and adopted by the world body, including UNSCEAR, its primary use was as a Cold War bargaining chip to force cessation of nuclear weapons testing.  The fear of radiation that took over the worldview was a side-effect.... Although rarely discussed, LNT does not take into account the organisms immune system, biological recovery time between doses or other relevant mechanisms that operate at low doses on an actual organism versus cells in a petri dish.

Forbes’ detailed article further explains: "UNSCEAR also found no observable health effects from last year’s nuclear accident in Fukushima.  No effects.  The Japanese people can start eating their own food again, and moving back into areas only lightly contaminated with radiation levels that are similar to background in many areas of the world like Colorado and Brazil."

The threat of terrorism now makes it vital for American civil authorities to properly understand the real risks involved. Imagine the problems that would arise from police and firemen running away from a dirty bomb attack based on false information about exposure to low doses of radiation. A city could be put in chaos.

I first learned about this reality from attending meetings of Doctors for Disaster Preparedness, run by the wise Dr. Jane Orient. She explained how after 9/11 she found that the Tuscon, Arizona fire department had been given radiation detectors showing 15 millirem as the threat level. She herself then provided them with more realistic detectors.

Thankfully, there is (slow) international progress in better understanding radiation risks. For example, the United Nations Scientific Committee on the Effects of Atomic Radiation has finally admitted that we can't use the LNT hypothesis to predict cancer from low doses of radiation.

An excellent little book titled Under-Exposed describes radiation effects (and even the medical benefits of low doses) in great detail. For converting different measurements in the confusing world of radiation herewith is a very useful chart calculator. Another link shows specific health effects from different radiation levels.    

The threat of homegrown terrorism is not going away. Washington must prevent future panics, unnecessary evacuations, and accompanying economic catastrophes by explaining to the American people the real levels of radiation risk.