April 14, 2004
"Dirty Bomb" Preparedness Discussed at Conference
Government and public health authorities should make sure the public understands the risks presented by radiological “dirty bombs” before one is ever used to terrorize a city, according to Jonathan Links, PhD, a radiation expert and professor of Environmental Health Sciences at Johns Hopkins Bloomberg School of Public Health.
“It is important to spread risk assessment messages now, before an event, because it will be too difficult to do it during an event,” Dr. Links told more than 120 public health and law enforcement professionals from the Mid-Atlantic region attended an April 12 conference,“Dirty Bombs II: Current Concepts in Radiation Terror Preparedness and Response.”
“Dirty bombs” or radiological dispersion devices (RDDs) are not nuclear bombs or atomic bombs. They are conventional explosives, like dynamite, packaged with radioactive material that is spread by the bomb’s blast. Although no one has ever used a dirty bomb, many terrorism experts believe they are a likely threat, because they would be easy to assemble and use.
According to Dr. Links, clearly explaining the risks associated with radiation exposure is an important but difficult task for public health officials because there are few absolute answers. He explained that the average person is naturally exposed to about 300 millirems (mrem) of ionizing radiation each year. While a dose of 100,000 mrem will cause burns and a dose of 600,000 mrem is lethal, there is no “100 percent safe level” against the long term risk of cancer or genetic defects. Overall risk can be decreased by reducing the length of exposure to the radiation and increasing the distance from a contaminated area, but the risk cannot be totally eliminated.
“A dirty bomb is a psychological weapon rather than a physical weapon,” said Dr. Links. He referred to dirty bombs as “weapons of mass disruption” because of the fear they would generate rather than number of people that would be killed in a blast.
For the past several years, Dr. Links has worked with the City of Baltimore to develop its plan for handling a dirty bomb emergency. Baltimore is one of the only cities in the country to have such a plan, according to Dr. Links. As a first step, all City fire fighters and emergency responders are equipped with pocket-sized meters to detect radiation in the environment. Once radiation is detected, the City’s radiation strike team, of which Dr. Links is a member, is dispatched to determine the amount of radiation present, to calculate how far the contamination has spread and determine the safest course of action.
In addition to Dr. Links, conference attendees heard presentations from the Baltimore Fire Department’s hazardous material team and the Police Department’s bomb squad. The conference was sponsored by the School’s Center for Public Health Preparedness and MidAtlantic Public Health Training Center.--Tim Parsonspaffairs@jhsph.edu .