BY CHRISTOPHER HAWLEY
Detecting potential weapons of mass destruction (WMD) materials can be difficult. It is not something we do regularly and on occasion requires devices and technologies we do not commonly use. There is also an extreme amount of stress involved in a potential WMD situation. One issue compounding the detection of potential WMD materials is our comfort level in using detection devices. For the most part, we are comfortable with chemical materials but less comfortable with biological or radiological materials. Additionally, there is no detection device that covers all of the potential threats.
Before we discuss the various technologies, we should review how to properly collect samples. Along with detecting potential WMD materials, the fire service must also do the following:
- field sampling for risk-based response categorization,
- sample collection, and
- sample analysis.
One of the overall goals in a WMD situation is to successfully prosecute the bad guy. Although the fire service typically is not a primary player in the prosecution of crimes, I am sure nobody would want to be the reason for a bad guy’s going free. Properly collecting evidence is critical to achieving this goal.
COLLECTING SAMPLES
Emergency responders and haz-mat personnel should establish a good working relationship with their local Federal Bureau of Investigation (FBI) WMD coordinator. Every FBI field office has at least one WMD coordinator who liaisons with local responders and assists with WMD matters. The FBI also has 27 haz-mat response teams throughout the United States and maintains a hazardous-materials response unit (HMRU) from the FBI Laboratory Division at Quantico, Virginia. The FBI has significant resources to investigate a potential WMD incident. Even with its vast resources, assistance from local responders is usually necessary. A significant issue regarding the investigation of a potential WMD event is that the gold standard of evidence collection is laboratory analysis at an approved laboratory. The findings of current field detection devices (though they may be the best in the business) may not be admissible in court. Furthermore, the potential exists for conflicting results obtained from field detection equipment and the diagnostic laboratory, which may hinder a successful prosecution.
To successfully prosecute a potential terrorist, some simple rules must be followed. When involved in a potential WMD event or one that could be a federal crime, always consult with your FBI WMD coordinator. When collecting samples, always follow the rule of halves. When you collect material, divide it in half and place half into a proper container. Send that half to a certified FBI/CDC Laboratory Response Network (LRN) laboratory for analysis. The other half of the material can be used to make public safety decisions and can be field-tested using any methods available to you. The results obtained from the LRN could be used to prosecute the bad guy. If there is a potential WMD threat, your local FBI contact will initiate a threat assessment conference call with the HMRU and the FBI WMD Operations Unit. The HMRU will have a scientist and a haz-mat officer on the call to help you properly collect samples, tell you how many to collect, and assist in field screening them for submission to the LRN laboratory. The type of container you should use depends on the type of evidence you are collecting, but the container should be certified as clean and sterile. Collect the material using certified sterile collection equipment, and ensure that the chain of custody is strictly followed.
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Remember that law enforcement is responsible for collecting evidentiary samples. In the case of WMD terrorism, that task falls to the FBI. If your assessment of the scene indicates the likelihood of a terrorist act, or if your samples submitted to the LRN test positive for WMD materials, the HMRU most likely would deploy to process your site as a WMD crime scene and gather evidence and evidentiary samples. Once the public safety issues have been addressed at your WMD scene, consider securing it as a crime scene, and pull all personnel from the hot zone.
PURCHASING WMD DETECTION DEVICES
The number of devices used to detect potential WMD materials seems to grow every week. It is almost impossible to keep up with the number of new devices entering the marketplace. This article focuses only on the technologies used by the devices, as opposed to the individual device.
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When looking to purchase WMD detection devices, several key factors should figure into your decision:
- Ease of use: Ensure the device can be used by everyone. It makes little sense to purchase a device that only a handful of responders can operate. In some situations, the best operators will be unavailable.
- Upkeep and maintenance: Less upkeep and maintenance means the device won’t nickel and dime your department to death, and it ensures that the device will be ready for use when needed.
- Threshold of detection and its response time: Although most of the devices have comparable levels at which they detect, all pertinent data should be carefully studied. Independent third-party testing for verification may be an option.
- Size, display, and alarms: It’s one thing to be able to detect potential WMD materials, but it is an entirely different challenge for the user to be able to handle the device; see the display; and hear, feel, or see the alarm.
CHEMICAL DETECTION DEVICES
This category has the most devices to offer and uses a variety of technologies to detect potential WMD materials. Other than for radiological detection, this field has the greatest history and significant military influence. No matter what detection technology you choose, keep in mind that all of the devices have false positive issues and that all of these devices are extremely sensitive, far more sensitive than any devices we have used previously. For example, most of these devices have the ability to detect in the parts-per-trillion range, which is significantly more sensitive than a flammable gas detector found in a four-gas detection device (LEL, O2, CO, and H2S). It is important to have more than one detection tool in your toolbox and to employ several devices when involved in a potential WMD incident. Never rely on one test to obtain your results. Doing so may embarrass you and could also compromise public safety.
The simplest method of testing in this category is to use test strips. Included in this group are M8 paper and M9 tape, which are military-style test strips. Both can give false positives but are inexpensive and easy to use. M8 paper indicates whether the material is a nerve or blister material and has a separate test for VX agents. The M9 tape indicates only that you have located a potential nerve or blister agent. It does not differentiate between the two groups. A new version of the nonmilitary style M8 test strip available commercially incorporates the M8 test strip technology into a badge that can be worn by a responder.
The next category of chemical agent detectors includes colorimetric tubes. They are the most accurate of all of the detection devices and are an economical choice for detecting WMD materials. Although they offer a high degree of accuracy, colorimetric tubes are not 100 percent foolproof. Responders should always follow the accompanying instructions to ensure an accurate test. Several manufacturers provide WMD detection tubes; most are comparable to one another as far as cost and operation. The keys to success with colorimetric tubes are reading and following the instructions. There are three types of colorimetric sampling systems: single tubes, multitube banks, and electronic chips. The single-tube type is most commonly used in the haz-mat response field. In the WMD response field, the multitube banks have the greatest market share. The colorimetric chips are used only for standard hazardous-materials responses; currently, there are no chips available to detect military WMD materials such as nerve agents and mustard agents.
With colorimetric tubes, the type of sampling required determines the best type to use. When confronted with a single material to sample, it may be best to use single tubes, especially when the type of threat agent is known. When investigating the possible use of a WMD material in or throughout a building, and where specifics are unknown, the multitube bank may be the best approach. The colorimetric chips can be used when the threat material is a standard industrial chemical such as chlorine or ammonia.
 (4) The electronic chip system is a colorimetric test for standard industrial materials. Electronic chips are available for a variety of chemical materials. |
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 (5) All evidence should be screened for the presence of fire, corrosive, toxic, and radiation hazards prior to shipment to a laboratory. |
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Although the colorimetric tubes yield the least amount of false positives, they have some disadvantages—primarily the time required to complete a test. Most tubes take a significant amount of time to complete the testing. In some cases, it can take 20 minutes to complete a test. A test can be conducted only in one area at a time, and the first responder must stay in that area to successfully test the atmosphere. The test is a one-time test. Once you have used a tube, you cannot use it again. Another use for colorimetric tubes is confirmatory. If other detection methods yield a positive result, you can use the colorimetric tubes to confirm the results.
The electronic devices category includes several technologies for chemical detection. The three major categories are ion mobility spectrometry (IMS), surface acoustical wave (SAW), and flame spectrophotometry. Emerging technologies are discussed later. At the responder level, these devices try to identify a potential WMD material using comparable methods. While the science and methodology differ, these detectors attempt to compare a chemical signature of a WMD material with a list of signatures stored in a database. If a close match is found, the device reports that it has located a potential WMD material. Every one of these technologies has issues with false positives. The SAW technology seems to have the least number of false positives. On the downside, the SAW technologies have the highest detection threshold for some materials. All of these devices have long response times; in some cases it may take up to 90 seconds to report a reading for low levels of materials. At high levels, they respond pretty quickly and are all comparable. Where they differ is in the detection of other materials, and some have other applications. Some of these devices can detect industrial materials such as chlorine and ammonia. Other devices can detect mace, pepper spray, and radiation. One of the best devices on the market can detect WMD chemical agents, common explosives, and common street drugs. From a WMD response perspective, this device would have the most appeal. The most common materials a bad guy is going to use in a WMD situation are explosive in nature. Perpetrators are usually also mixed up in drugs. This device can handle both. Although the price for this device is a little too high for most response agencies, it is an essential device for those in the WMD response business, as it covers most potential WMD materials.
When looking to purchase an electronic chemical WMD detection device, look at the options available to you. Choose a device that can be used for more than WMD incidents and that is easy to use. Some of the devices have significant upkeep issues. Hands-on training and experience are the keys to success with these devices. While none of them is perfect by design, some training and education about what makes them alert goes a long way. Their inherent sensitivity is also their biggest downfall. When chemicals are in the air and some part of their chemical structure mimics a WMD material, there is a good chance the detector will indicate positive. If a device has a false positive, the worst harm done is that you may take actions to prevent injury or death. On the other hand, if a device indicates a false negative (as in the case of some biological agent detection devices), responder inaction may cause death or injury.
BIOLOGICAL DETECTION DEVICES
This area of detection seems to have created the most controversy among emergency response agencies. Early technologies didn’t work well, and there are still gaps in the technology despite some improvements. With potential biological agents, the gold standard of detection is (and probably will be for awhile) laboratory analysis. Taking a sample to the laboratory yields concrete answers that are legally defendable in a court of law. Methods for identifying biological agents on the street can be problematic depending on the type of device. As with all other WMD detection devices, relying on one type of technology can be problematic. Use a multidevice approach.
Biological detection devices can be divided into two groups: broad spectrum and specific. The broad spectrum test alerts users to a large number of potential biological agents; the specific test kits identify one very specific material at a time. One broad spectrum device alerts the user to the presence of potential biological material and looks for specific microbes common to the biological threat agents. It appears that this test has more benefit, as opposed to a test that just indicates the presence of proteins. It is quick, and a bacteria test and a toxin test can be completed in 15 minutes. Both are easy to use and provide a low-cost starting point. One thought is that if you receive a negative test for both bacteria and toxins, then you can proceed to test the material using chemical testing methods. If you receive a positive, then you would proceed to perform other biological testing.
The most common method of testing for specific biological agents is the handheld immunochromotographic assays, commonly referred to as “HHAs.” There are several types on the market; their reliability varies. Their threshold of reporting results also varies. When using HHAs, always use the test reader. Never rely on a human to interpret the test results on the cartridge. Reports indicate that when a human interprets an HHA test strip, accuracy is less than 30 percent. Using an electronic reader dramatically improves the accuracy of the test results. When considering the purchase of HHAs, ask the company for independent third-party testing data. Possible indicators of device quality are the number of tests and the specificity of the data. The quantity of available information and the quality of the data generally indicate how well one biological test will perform over another. None of the HHAs claims to be 100 percent accurate, and third-party testing has indicated a range of 7 to 97 percent accuracy.
Another factor for HHAs is the threshold of reporting, or how low the device can detect the sample material. Some devices will indicate at a spore level of 4,000 spores, whereas others may report at 100,000 spores. On the other side, one problem some HHAs have is they can be overwhelmed by a large quantity of spores or a more pure sample. When these devices are overwhelmed, they tend to provide a negative test, which, obviously, can be very dangerous. The lower the number of spores required to cause an alert, the better the device. Ensuring that the device can’t be overwhelmed by a high spore count is also very important. Do your homework, ask a lot of questions of the manufacturers, and ask for the third-party test data.
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A new method of biological agent field detection now available to responders is known as polymerase chain reaction (PCR) technology. This test takes the DNA from a sample and replicates the DNA sequence multiple times. The replication is done in an internal thermocycler, which heats and cools the sample. In the PCR buffer solution, there are fluorescent probes that bind to a specific DNA sequence. The PCR unit reads this fluorescence; as more DNA is replicated, the more the sample fluoresces, which is detected by the instrument. PCR technology is a good and sound technology and has been used in the laboratory for many years. This technology holds some promise for the future but currently only tests for a handful of agents, and each agent must be tested for separately. One drawback is that some materials in environmental samples and even some collection tools (e.g., cotton swabs) can give false negative results. Furthermore, microorganisms that occur naturally in the environment may give false positive results if they contain DNA sequences similar to those being detected. When comparing PCR units, it is important to know the number of steps and the complexity of the steps required to get a sample to the PCR unit. The easier the process and the fewer the steps required to get a sample to the device, the greater the success in using a biological testing device. Current versions of field PCRs have not been on the market for very long, although their lab-based counterparts have been around and have been used reliably for quite some time. Time will tell how accurately the street versions will perform. Initial lab results are pretty positive.
Most of the problems with biological testing devices are directly related to the handling of the sample prior to inserting the sample into the variety of devices. In many cases, the device requires that a specific amount of material be inserted into a test cartridge or device. In some cases, reagents or buffer solutions may have to be mixed or added. Read the instructions with each kit, and follow them carefully. Even the most experienced and most knowledgeable responders should have the manufacturer’s instructions or cheat sheet beside them while performing the test. Biological tests require only a very small amount of sample material. Unfortunately, emergency responders usually follow the mindset that bigger must be better. When deciding which instrument to purchase, compare the number of steps it takes to perform a test, ask about the complexity of the steps, and think about the likelihood of mistakes. If the “A” team isn’t on the incident, could the “B” or even the “C” team make the device work as planned?
RADIATION MONITORING
For first responders, there are three basic categories of radiation detection devices: pagers, dose rate meters, and source identifiers. In some cases, specific devices may handle more than one task. The simplest and most essential device is a radiation pager, which alerts responders to an increase in the radiation level above background radiation. The level of background radiation varies across the country, but is the normal amount of radiation that is present. Several pagers are on the market. Some alert the user only to a level of radiation that is higher than that in the initial background. There may be a numeric indication of how high the level is above background, such as two times higher than background. Unfortunately, these types do not let you know what the starting background level is. At least two other devices provide the same alerting procedures combined with a dose rate. When you turn the devices on, they provide a reading of the background level of radiation. If the level increases, the devices go into alert and provide a reading of the level of radiation.
 (8) All detection devices should be easy to use and should require little training and preparation. Shown here is an FTIR detection device that is one tool for identifying a material. |
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The most common radiation-monitoring system reads in dose rate, usually in roentgens per hour (R/hr) or comparable units. Some detector types detect and quantify various types of radiation more efficiently than others. No single detector (instrument and probe) is 100 percent efficient in detecting and quantifying alpha, beta, and gamma radiation in a single measurement. Tailor your choice of radiation detector to the type of radiation expected. The effectiveness of the selected detector depends on instrument settings, calibration, and operator technique. For example, the detection of alpha particles takes a special probe, such as a Geiger Muller pancake probe or a scintillation probe. Alpha particles are made of two protons and two neutrons, pretty big in the molecule world, and have a range in air of about 2 to 3 cm. Therefore, to detect alpha radiation, the probe has to be very close to the source. When checking someone for potential alpha contamination, the responder must move the probe very slowly and closely over the suspect area of contamination. Beta radiation and gamma radiation are more penetrating and do not require the user to be as close to the source. You must take your time when checking for potential sources of radioactive material because of instrument response time, which can be on the order of 3 to 5 seconds.
In addition to providing a dose rate, some radiation detectors can also identify isotopes (common isotopes that have specific gamma ray energies). Some units can track a small number of potential sources; others can track about a hundred different isotopes. Some units are smaller and can be held with one hand; others require two hands for operation. Their standoff distances and their rate of response also vary, so do your homework. Having a device that can detect radiation levels and provide gamma ray identification is pretty exciting, although the cost for these devices is pretty high.
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One issue with radiation detection devices is their overall ruggedness and resistance to the elements (humidity and water). Some of these units were not designed for emergency response work and, if used for that purpose, could break easily. When looking to purchase a radiation-monitoring device, choose one that is easy to use, responds quickly, and is compatible with the job function.
ADVANCED AND NEW TECHNOLOGIES
With the influx of money for WMD response and research, several new technologies are making their way to the street. One of the major drawbacks with these new devices is their cost. Many of them are very expensive, sometimes more than $100,000.
Some of them have crossover potential into several other areas, such as chemical and biological detection. One technology creating some excitement is Fourier Transform Infrared Spectroscopy or FTIR. The general operating principle behind FTIR technology is that it shoots an infrared light source at a sample. The sample material allows some of the light to pass through while absorbing other parts. By reading the resulting type and wavelength of the remaining (and missing) light, a spectrum can be developed. This spectrum can be compared with others in the library. The computer provides potential match and a list of other possible matches. These devices are easy to use and can quickly provide some potential identifications. The devices can identify solids, liquids, and gases and have a list of items they can’t identify. When attempting to identify biological materials (which have proteins), the units will not specifically identify the material. Some FTIR units will alert the user to the presence of proteins and advise them to follow a biological protocol. One of the major issues and shortcomings of these devices is their inability to identify mixtures. The more materials included in the mix, the more problems for the device, as it has a tendency to miss some of the materials. Manufacturers have been very forthright about this limitation and clearly state that FTIR is just one tool that can be used and that it should not to be used to provide an absolute identification. This mixture problem is not unique to FTIR technology. The problem also exists with other types of devices, but first responders are using the FTIR unit to identify materials. Another important point about FTIR technology is that it is limited to molecules containing covalent bonds. Salts and metals have little or no IR signature. One example is cyanide salts. There is potential for an FTIR to incorrectly identify a material that does not contain covalent bonds.
Another unit in the advanced category of detection is the gas chromatograph and mass spectrometer, commonly referred to as a GC/MS device. It is two instruments in one and is the device closest to being a near perfect detector. The GC portion of the device takes an unidentified material and separates it into the various elements that make up the material. It separates those elements by heating the material and sending the materials through the GC column. The GC column allows the material with the lowest boiling point to travel up the column into the mass-spectrometer portion of the device. The MS portion of the device (in simple terms) further separates the material and, through the mass of the material, compares it with known spectra in the library. The mass and spectra of many materials are known quantities, and the matches are displayed on the screen. Each of the material’s components is identified; in some cases, the name of the material is provided. In other cases, the GC/MS devices require the user to recognize that the six chemicals listed make up sarin nerve agent. In those types of situations, it might be helpful to have some responders with a chemistry background. Operators should have at least a week of training for these devices, which require regular calibration and maintenance. Depending on the unit, these expenses can approach several thousand dollars a year.
Other products that will hit the street soon use Raman spectroscopy and ultrasonic detection technologies. The military has used ultrasonic detection devices for several years. Ultrasonic detection is accomplished by shooting ultrasound waves into a container and then reading the echo that comes back. The military uses these devices to identify the materials inside potential chemical munitions. As with many chemical agent detection devices, the basis for this technology is to use a specific method that is transformed into a spectra or fingerprint. The spectra is then compared with a spectra in the library. When used in a military application, these devices have limited spectra libraries, which will have to be expanded for civilian street use.
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The Raman unit uses a laser concentrated on the sample substance. When the laser light hits the sample, the light may be absorbed by the sample or may travel through the sample. Some of the light may become scattered, which is then read by the Raman unit. When the laser light hits the sample, the resulting collision may cause a photon to lose or gain some energy. This change in energy provides the basis for the spectra.
An advantage with Raman over FTIR units is that it uses a developed spectra to provide its identification. The main advantage of Raman is that the sample can be analyzed while it is inside a container. It does not require the sample to touch the testing surface. You can collect a sample in a container; as long as the sample container is able to access the device’s sampling port, it can be tested. Another advantage is that you can test samples that are in water. The Raman device has limited ability to minimize the impact of the water in the resulting spectra. The FTIR spectra can be overwhelmed by any water in a sample.
The Raman and FTIR units have trouble with mixtures. This problem will require some resolution for successful detection of potential WMD materials.
DECIDE ON WHAT BEST PROTECTS YOUR COMMUNITY
Detecting WMD materials is difficult and can be a very frustrating process. You need to have a variety of tools in your toolbox, many of which are quite expensive. Technology is not quite to the point where you can have one device suited for all needs. That day is still a long way off. Responders should look to a matrix or flowchart system of detection that uses a variety of tools. The gold standard at the top of the list should always be to collect a sample for laboratory analysis. An effective thought process behind any system is one that eliminates possible materials. Having devices that are easy to use and have applications in other areas besides terrorism events is an important consideration.
Properly trained responders should be backed up with 24-hour technical support. Responders should also add scientific professionals to their response systems. Local chemists, biologists, and other professionals should be part of the response system and should be consulted on a regular basis.
It is difficult to keep abreast of all the technologies that exist for detecting WMD materials. Having a system in place that best protects your community is essential. Terrorists have hundreds of potential weapons from which to choose. The best system is one that covers the most likely scenario, followed by all of the other possibilities.
CHRISTOPHER HAWLEY, a 22-year veteran of the fire service and a haz-mat responder for 15 years, is a project manager for Computer Science Corporation and is responsible for international WMD and haz-mat training provided for the DoD-DTRA International Counterproliferation Program. He retired as a fire specialist from the Baltimore County (MD) Fire Department, where he served as the special operations coordinator. He is the author of a number of texts including Hazardous Materials Incidents and Air Monitoring & Detection Devices (Delmar Publishers, 2004) He is the co-author, with Greg Noll and Mike Hildebrand, of Special Operations: Response to Terrorism and HazMat Crimes (Delmar Publishers, 2001). Hawley is the owner of FBN Training & Consulting, a company that provides emergency response training worldwide.
PURCHASING CONSIDERATIONS
When considering the purchase of WMD detection devices, you certainly want to buy the best device for your money. One primary consideration is not to start looking at devices but to focus on the technology. Choose a detection technology (or combination), and then look at devices. Compare each device side by side; then compare them using the questions below as a guide.
- Is the device easy to use?
- Does it have other functions that apply to typical haz-mat events?
- What disposable supplies does it require?
- Is there a shelf life for the materials? If so, how often must they be replaced?
- What is the cost of the disposable supplies?
- What maintenance does the unit require?
- What are the maintenance costs, and how often must maintenance be performed?
- What are the lower detection limits (for all materials, not just the main one)?
- What about false positives and false negatives?
- Can the test be saturated by a pure sample? If it can, what happens?
- Is 24-hour technical support available (and who will provide it, a salesman or a specialist)?
- What are the battery considerations (type, battery life, run time, recharging time)?
- What training comes with the device?
- What about software upgrades (ease and cost)?
- Who conducted the third-party testing of the device? Can you obtain a copy of the test results?
