Relating rad to risk

A collapsed building with victims trapped. A man with a gun. Fifty rems of radiation. Since responders don’t necessarily know the relative risks, is current radiation detection too good?

The death last November of Russian dissident and former spy Alexander Litvinenko in London after consuming a lethal dose of deadly polonium-210 served as a reminder of the threat of radiation as a weapon of mass destruction, and whether the first responder community is ready to deal with it.

At first glance, readiness to meet radiation threats looks encouraging. Most hazmat and radiation experts tend to agree that field radiation detection technology is no longer an issue, because the detection equipment exists to sufficiently arm first responders for radiation encounters.

"The current generation of field radiation detection products adequately meets the needs of first responders," says Mike Gavin, emergency manager for Fort Collins, Colo.

Capt. Sam Konkel, Sedgwick County (Kan.) Fire Department, says, “Unlike chemical and biological detection, I can’t imagine what else we could need to detect radiation.”

And Raymond H. Johnson, president and director of the Radiation Safety Academy, agrees that the radiation instruments available to first responders are more than adequate for making good emergency decisions.

The issue, therefore, is not about the instruments, but more about the ability of first responders to understand and interpret instrument readings.

“If anything, our ability to detect radiation is too good,” Johnson says. “This can lead first responders to conclude that if radiation is detectable, it is automatically dangerous.”

He says there have been several occasions when first responders have evacuated people from residential or city areas based on a radiation reading of twice the normal background. "Such decisions, while they may seem prudent for radiation safety, are the result of responders not understanding that background radiation readings frequently fluctuate and a reading of twice background is well within the normal range of variation."

Hot time

Mark Linsley, a Penn State University health physicist who teaches first responders about radiological hazards, says that to successfully manage a radiological incident, responders need to be able to make two distinct radiological hazard determinations: detection of radiological contamination and the intensity of the radiation field emitted by the radioactive material.

"It is extremely important that first responders understand and appreciate these concepts, because there can be significant levels of contamination, but little to no detectable radiation,” he says. “The recent polonium-210 poisoning is one example of this."

Though many responders would like one radiation instrument to make both measurements (detect radiological contamination and measure field intensity), no single instrument does both simultaneously.

"It takes two different types of instruments to assess radiation intensity and radioactive contamination," Linsley says. Instruments with interchangeable probes have appeared on the market, but essentially you are still looking at only one hazard at a time.

Nevertheless, developments in handheld instruments capable of identifying specific gamma-emitting isotopes have made an important contribution.

"These specialized instruments allow responders to distinguish between radioactive material used every day for medical diagnostic and therapeutic purposes, and material that may be intended for a more sinister use," Linsley says.

Several radioactive isotopes emit radiation of such low energy that they can’t be detected with any conventional contamination-monitoring equipment. These low-energy isotopes do not pose an external, whole-body radiation hazard, but they can become a significant contamination problem.

"This is why proper training on hazard recognition is necessary to enable responders to take proper protective action, work to minimize the potential spread, and contact the appropriate radiological authority to assist with scene assessment, radiological evaluation and additional response actions," Linsley says.

Hot topic

Before responders make expensive evacuation decisions, Johnson would encourage them to repeat measurements for confirmation, and above all to ask questions before rushing to a conclusion.

Many responders have little understanding that they can enter a high-radiation exposure area for a short time without danger to themselves. If there are significant medical needs that require attention at the scene, they should be addressed without any regard for radiation, Johnson says. “Forget about the radiation and proceed with normal life-saving functions first.”

Most responders also don't understand how difficult it is to be seriously harmed by radiation. "It takes a considerable amount of radiation to harm someone and the circumstances for harm are very unlikely," he says.

In classes he teaches for first responders, Johnson likes to show how household glassware containing uranium oxide as a coloring agent can set off a conventional Geiger-Mueller detector.

"For many first responders, a screaming GM detector means they should evacuate everyone within 1,500 feet, yet the GM readings on my glassware drop to normal background at a distance of one or two feet," Johnson says.

Johnson also uses americium-241 as a class prop. This isotope, commonly used in household smoke detectors, will register 7,000 milliroentgen per hour on GM detectors. When Johnson asks the responder class how far they needed to back away for the reading to drop to the acceptable public dose limit of 2 milliroentgen per hour, replies range up to hundreds of feet. In fact, readings drop in less than five feet.

Many responders are ambivalent about these facts. "First responders tell me their job when they detect radiation is to secure the area, not to make decisions about the hazard or risk," Johnson says. "They will implement quarter-mile evacuations with little or no actual data."

For many first responders, a chattering GM detector is enough information to implement an evacuation, without regard to the type of radiation or its normal range of behavior, he says.

It’s about time

The problem is, radiation is not intuitive. Some guidelines exist that recommend responders not unnecessarily exceed a dosage of 5 rems, nor exceed 10 rems except to save lives, or 25 rems except to save large critical infrastructure assets.

"First responders don’t know what those numbers mean," says James L. Conca, director of the Carlsbad Environmental Monitoring and Research Center, New Mexico State University. He says the 5 rem figure is an OSHA workplace limit, which has the same danger quotient as not having an ergonomic chair in your office.

"If you're at a disaster or accident scene, you don't care about ergonomic chairs," he says. "A more appropriate number might be 50 rems. OSHA says you should never exceed 50 rems, no matter what. But 50 rems is nowhere near as dangerous as running into burning buildings, and responders do that all the time. Police chase people with guns, but if you throw 25 rems at them, they don’t know how to evaluate that risk."

Radiation is all about time.

"If you need to save someone, get in and get out in 60 seconds," Conca says. "It’s hard to get any kind of a dangerous dose in 60 seconds. If you’re doing triage, then you may start accumulating doses. It's linear with time, but saving life is much more important than getting a little dose. A little dose of radiation is simply not going to do anything."

Measuring the risk

Radiation released into the environment is measured in units called curies. (A curie, abbreviated Ci, is 37 billion particle emissions per second.) However, the dose of radiation a person receives is measured in rems (Roentgen equivalent, man), millirems (thousandths of a rem, or mrem) or Sieverts (1 Sv equals 100 rem).

Rems relate the absorbed dose in human tissue to the effective biological damage from the radiation. There are no symptoms resulting from doses up to 5 rems. At 20 rems, there is a temporary reduction in red blood cell count. Mild radiation sickness can be expected with a dose of 50–100 rems, and 100–200 rems will inflict light radiation poisoning, which is 10% fatal after 30 days. Severity and the fatality percentage increase from there.

Familiar sources of low-level radiation are chest X-rays (10 mrem), mammograms (70 mrem) and GI tract X-rays (250 mrem). In the U.S., the average person is exposed to an effective dose equivalent of approximately 360 mrem (whole-body exposure) per year from all sources: soil, air, television, computer monitors, food, dental crowns, air travel and others, according to the National Council on Radiation Protection & Measurements (NCRP Report No. 93).

Rules of thumb exist in the field, offering general approximations of acceptable counts per minute or per hour, but they’re valid only if you know the types of radioactive material involved and the technical limitations of the detection instrument being used.

Experts question whether first responders know if or when they should use these approximations. Linsley’s caveat is to keep it simple by using one instrument suitable for checking for radiation and one instrument suitable for evaluating that radiation hazard.

"The minimum radiation-detection instrumentation one should have,” Linsley says, “is a contamination survey meter equipped with a pancake-style Geiger-Mueller probe capable of detecting alpha, beta and gamma radiation, and a separate radiation survey meter with a range of at least zero to 200 milliroentgen per hour."

The contamination survey meter by itself is not enough, he explains, because it isn’t telling the responder the intensity of the radiation field, which could be a source of immediate harm, and because it might not distinguish between types of radiation (alpha, beta and gamma).

"Radiation is the easiest hazard to detect," Linsley says, but it can be very difficult to assess accurately. He sometimes tells his classes that radiation is like a skunk: “You can detect it long before you have to deal with it."

What's hot, what's not

Overall, there is a concern that even after all the funds allocated since 9-11, responders are no more efficient at dealing with radiation than they were before. Some of this is legacy. Of firefighter calls, generally 80% are medical, 15% fire, 2% miscellaneous and 3% hazmat. And few, if any, hazmat responses involve radioactive material. Most fire departments also deal with inspections, planning, hydrant testing, equipment and station maintenance, mapping, fitness, rescue, and training new personnel.

Konkel notes that all this leaves little time to train for radiation, a hazard that "until now, has had a low probability of happening."

Gavin says the real issue is whether responders see the need to have detection equipment and perform routine monitoring, and whether they are currently monitoring motor vehicle accidents involving common carriers, commercial structure fires and routine building inspections for radiation.

However, he says, many fire departments are beginning to see the benefit of routine radiation monitoring on a variety of incidents, especially accidents involving commercial carriers such as FedEx and ups. About 3 million packages of radioactive materials are shipped each year in this country, whether by highway, rail, air or water, according to the Nuclear Regulatory Commission. Even if each package is in transit for only one day, that means an average of more than 8,200 radioactive items are in transit on any day.

Hot tips

It's obvious, then, that radiation is a hazard that any responder could encounter at any time. Education in how to recognize the hazards and training in the proper operation and limitations of detection equipment and survey techniques are therefore essential.

Linsley offers these tips:
• Work with federal and state radiation authorities to identify facilities in your area where radioactive materials are used.
• Develop contacts with the safety representatives at those facilities to learn what radioactive material is used and at what levels, and what risk it poses.
• Identify and equip yourself with the instrumentation best suited to meet the level of hazards to which you may need to respond.
• Contact radiation safety professionals, such as the Health Physics Society <www.hps.org>, for guidance on choosing detection gear.
• Train. A variety of training resources are available, including the Department of Energy's Modular Emergency Response Radiological Transportation Training program.

"The biggest issue facing responders isn’t equipment, it’s knowledge and training," Konkel says. But some training manuals can be dense, almost impenetrable. When Konkel reviewed a publication developed to assist responders on radiological incidents, he found 70 pages of ponderous text.

"That might be good for some technicians," he says, "but anything over a couple of pages is too much for most responders."

Anticipating this problem, Conca’s center at New Mexico State University came up with a one-page, 12-point response guide for dirty bombs that responders can laminate and carry in their vehicles. <www.cemrc.org/dirtybomb/12pointGuidance.pdf>

However, before training and guidelines will have much effect, the response paradigm must shift. Gavin says responders need to change their mindset regarding radiological concerns.

"We should start monitoring for radiation on more incidents than we currently do,” he says. “Maybe we should have at least one person on the company wear a dosimeter. Radiation is a silent killer. Who knows what we have been exposing our first responders to?"

Gavin equates radiological concerns with monitoring for carbon monoxide and cyanide, paradigm shifts in response that happened only after it was realized how much damage they were causing first responders.

He warns: "Responders need to continue to be proactive and look at other hazards we may be exposing ourselves to."