Proposal on 'Dirty Bomb' Attack Would Accept Higher Exposure
Published: January 5, 2006
WASHINGTON, Jan. 4 - The Homeland Security Department, preparing for an attack by terrorists who would spread radioactive material, advised government officials on Tuesday that they should consider allowing people to reoccupy contaminated land and buildings even if they would be exposed to radiation at a level double what nuclear plant workers could legally receive.

The department published a document that emphasized trying to balance the health risk of radiation exposure with minimizing the disruption that a "dirty bomb" would cause.

If there is a delay in reoccupying areas evacuated because of contamination, the disruption and harm "could be inadvertently and unnecessarily increased," the department advised. Failure to restore important services rapidly could result in additional adverse effects on public health and welfare "that could be more significant than the direct radiological impacts."

The document, published in The Federal Register, listed precise exposure limits for emergency workers and the public immediately after a dirty bomb attack.

For the long term, it said, officials responsible for public health and safety should consider a variety of "benchmarks" in use around the world, some far higher than standards in use in this country to protect the public in routine operations and nuclear accidents.

Guidelines from the International Commission on Radiation Protection say that actions to reduce exposure to radiation, like evacuation or cleanup, may not be required until doses equal 10 rem a year, an amount that is about 30 times what the average American receives from natural and manmade sources of radiation, and double what power plant workers can legally receive.

It is also about five times as high as the maximum that power plant workers commonly receive in a year.

An opponent of nuclear power, Daniel Hirsch, of the Committee to Bridge the Gap, said the standard that should apply is the one that the Environmental Protection Agency uses when power plants are torn down, which is 25-thousandths of a rem per year, one-400th of the international standard.

But a spokesman for the Environmental Protection Agency, John Millett, said that when his agency's guidelines were set in 1991, with nuclear power plant accidents in mind, there was no consensus on what long-term exposure should be allowed.

Larry Orluskie, a spokesman for the Homeland Security Department, said the new guidance did not necessarily suggest using the international agency's number, but recommended considering its use, "depending on what the circumstance is, and what the environment is, and the state and local authorities' need for that area."

THE PRINT VERSION OF THIS ARTICLE CONTINUES: The newly issued document lists a variety of factors, including the cost of cleanup. Mr. Hirsch and a second antinuclear group, the Nuclear Information and Resource Service, said that the 10 rem figure would produce cancer or leukemia in one person in four who was exposed to that amount annually for a total of 30 years. The two groups called the advice "a nuclear Katrina in the making."

The department characterized its advice as a draft, because, it said, it would take public comment until March 6, but the advice takes effect immediately.

The document offered advice on both dirty bombs, a postulated weapon that is a conventional explosive laced with a radioactive contaminant, and on nuclear bombs that a terrorist group might smuggle into a city. Security experts say that a dirty bomb is far easier to construct and thus might be the more likely threat.