Responding to a Radiological Dispersal Event

By Eric L. Darois

Firefighters and other first responders from across the country can look to how their counterparts in Boston, Massachusetts, sprang into action in the immediate aftermath of the Boston Marathon attacks as a model to follow when conducting their own preparations and drills for a so-called “dirty bomb” attack that involves the use of a radiological dispersal device (RDD).

The word “radiation” can cause panic and make the initial response and triage of victims more difficult and chaotic. Training to prepare for a radiological incident should include a range of activities including receiving an education on the basic fundamentals of radioactive materials and their hazards, the proper use of radiation detection equipment, and methods to reduce exposure and control radioactive contamination. A key training objective for firefighters and paramedics should be to develop a clear understanding of how to safely treat and transport victims exposed to radiation or contaminated with radioactive materials.

A RDD is a mix of explosives with radioactive material, which could be in the form of powder or pellets; detonation carries radioactive material into the surrounding area. In the case of the Boston Marathon attack, where the two bombs were made from common household pressure cookers, the actual amount of radioactive materials dispersed by those devices would have presented an isolated threat to the people nearby. Most likely, injury from radiation exposure would be much less significant when compared to the physical damage caused by the blast itself. The panic and chaos that ensued following a RDD attack would disrupt triage and victim care, which is critically time-sensitive to reduce the number of fatalities.

Firefighters and other first responders should have radiation detectors in their response tool kits to monitor for radiation and contamination on arriving at the scene of an incident. Proper training in performing this monitoring is necessary because determining if radioactive materials are present is not as simple as turning a detector on and reading its display.

Many people do not realize that they are constantly exposed to background man-made and naturally occurring radiation, measured in the units of “millirem”. In fact, over the course of a year, United States residents receive an average radiation dose of 620 millirem. Sources of this dose include cosmic radiation, radioactive materials in the earth, diagnostic and therapeutic medical procedures using radiation and radioactive material, and others. Therefore, many radiation detection instruments will indicate that radiation is present whenever they are operating. Background radiation does not require special safety controls as it is part of everyday life. If radiation levels are at background levels, no special measures need to be taken. It is important that a first responder not confuse the difference between background radiation levels and the increased levels caused by radioactive materials released by a terrorist attack that involve radioactive materials, as unnecessary panic could ensue leading to erroneous decisions.

It is also critical that the right type of instrument be used to assess the situation. Since there are many types of irradiations, first responders need to be trained to understand the types of expected radiations and the instruments to use in responding to an event involving radioactive materials. Instruments should be routinely calibrated or checked to determine the accuracy of their readings. Calibration of radiation detection devices should be done on an annual basis by the manufacturer or other licensed facility. Periodically checking the operability of radiation detection instruments using a field check technique can also ensure that the devices are working properly when they are needed. This technique uses a small radioactive “check source” to verify detector performance and is a common best-practice for this purpose.



Confirmation of contamination and/or elevated radiation levels alone should not trigger a rush to clear the scene, which could place injured victims at unnecessary risk. Lifesaving and other actions to secure the area from further terrorist activites at a radiological terrorist event should take precedence over radiological considerations.

Radioactive materials from a RDD will likely not create fallout that sweeps across a city, contaminating everything in its path. In an outdoor explosion, most of the airborne radioactive dust will normally settle to the ground within several minutes and will remain relatively close to the explosion site. In most cases, wearing masks and protective clothing will protect first responders from most exposure to contamination. For victims, simple measures such as removing outer layers of clothing and cleaning and dressing open wounds most likely are enough of a precaution to take before transporting them to the hospital.

Also, responders must define their radiation boundaries to provide awareness of contaminated zones and limit radiation exposures. The location and exposure rates of these boundaries will depend on the amount of radioactive materials dispersed and the physical size of the impacted area.

There are three methods of protection against external radiation exposure: reduce time, increase distance, and use shielding. The less time spent near the radiation source, the lower the exposure. The greater the distance from the radiation source, the lower the levels of exposure. Additionally, external exposure from the radiation source can be partially blocked by the use of shielding. Staying behind vehicles, buildings, and other objects can significantly decrease exposure. To reduce the potential of internal exposure from ingestion or inhalation of radioactive materials, responders must be trained on the proper use of protective equipment such as respiratory protection and protective clothing.

Responders will need to safely rescue and treat the injured and coordinate their transfer to hospitals, which should be ready to receive patients contaminated with radioactive materials. Proper training is also important for responders to communicate with emergency room staff to minimize panic when they hear the word “radioactive.”

Preparing for a radiological dispersal event should be built around two foundations: education and drills. It is a must to practice drills to reinforce basic detection and protection techniques. Also, have detection equipment set aside and readily available at all times. All responders should carry properly-calibrated radiation detectors, and hospitals should have survey capabilities.

It is also necessary to attend classes on the fundamentals of radiation. Understanding where radioactive materials come from, which levels of exposure are hazardous, and the types of materials responders may encounter will help responders make educated decisions when faced with such an event.

The most important thing to remember is that triage is the highest priority. Do not allow the presence of radioactive contamination affect the treatment of victims. With proper training, first responders and hospitals can safely and effectively treat victims of a RDD attack with the same with same speed, bravery, and compassion as they did in Boston.

Photo found on Wikimedia Commons courtesy of Aaron "Tango" Tang.

Eric L. Darois, CHP, MS, is a principal of Radiation Safety & Control Services in Stratham, New Hampshire. He is certified by the American Board of Health Physics and has a BS and MS in Radiological Sciences and Protection from the University of Massachusetts at Lowell. He has more than 35 years working in the field of radiation safety and provides training and consulting services to all industries that use radiation and radioactive materials.

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