BY CHRISTOPHER HAWLEY
During the past year, there have been changes to existing detection technologies as well as new developments in emerging technologies. The future looks bright regarding WMD detection technologies considering the several exciting developments on the horizon. The pace of change is rapid and, in some cases, it is difficult to keep up. This article focuses on the technical nature of the detection methods, not brand names.
UNDERSTANDING TECHNOLOGY
Once you understand the basic technologies, you can make an accurate comparison of competing devices. Many of the new responder technologies are moving from laboratory settings to street-level first responder environments. This change is not without significant issues. In the laboratory, there are a small number of persons who use one type of analytical device, and there may be one person who uses the same device every day. These people generally have an extensive background in chemistry or biology and have received training on the detection device. In the emergency service field, some may have comparable backgrounds and education, but they may not have the same daily experience using the various detection devices. When testing materials in the laboratory, the lab technician typically follows extensive testing protocols and processes. The focus in the laboratory is on quality control and quality assurance, and there are extensive steps taken to prevent cross-contamination. Extensive record keeping is normal, and the focus is on maintaining a scientific standard. In the first responder community, some maintain these high scientific standards but, given the conditions under which we operate, we can’t always meet the same level of performance. For some of the existing and emerging technologies, we must strive to improve our performance in these areas.
Some in the haz-mat response world are torn between the laboratory and the street. On one side, there is a need for quick and accurate information. On the other side, what does it take to get that information? Is it possible to train all of the responders on your haz-mat or WMD response team to perform laboratory-level analysis with your detection devices? Do you have just one or two persons per shift who can really make the devices perform? What if they are not available during a response? Responders need to push the manufacturers to provide easy-to-use devices and provide extensive hands-on training. We also need to increase our level of knowledge and understanding of the limitations of the various devices. At some point we may need to coordinate our efforts with the scientific community to carry out difficult testing procedures. On both the first responder and laboratory sides, many lessons need to be shared.
Even with the advances in detection technology, the gold standard for chemical and biological identification is the laboratory. In situations where a crime may have been committed or there may be terrorism implications, the laboratory analysis is all that can be used in a successful prosecution. No matter how sophisticated the street testing, the laboratory analytical result is the crucial evidence. Coordinating your identification efforts with your local FBI WMD coordinator and your nearest Laboratory Response Network (LRN) lab is always a good idea, as their focus is on evidence collection. Don’t be surprised when they recommend the laboratory analysis as the priority, as that is the only testing they can use. Even with advanced street-level detection methods, do not anticipate this to change any time soon, as the court system prefers definitive laboratory results. When performing testing and analysis, always divide the suspect material into two separate samples. One is for evidence; it is collected following evidentiary procedures and is never cross-contaminated. Use the other sample for street-level testing, and conduct any testing you desire. Coordinate with your local FBI WMD coordinator to ensure that the proper amount of material is collected for the evidence; use the smaller remaining amount for field screening.
CHEMICAL AGENT DETECTION TECHNOLOGIES
The major technologies for chemical agent detection continue to be Ion Mobility Spectrometry (IMS), Surface Acoustical Wave (SAW) technology, and flame spectrophotometry. All three have seen some advances in the software that drives the detection devices. The technologies haven’t changed, but many of the manufacturers have increased their instruments’ accuracy and sensitivities. There are still some issues with false positives, but many manufacturers have made significant progress. One detection device combines IMS and SAW technologies in the same unit. Using any combination of the three technologies provides for a more accurate detection device. The use of IMS technology allows for a low detection threshold and adequate accuracy; the SAW technology provides accuracy but does not have as low a detection threshold as IMS. The more manufacturers can work on accuracy, the better off responders will be.
There are still issues with the devices’ slow response times, false positives, and limited target chemicals. Chemical agent detection manufacturers should strive to achieve a response time of less than five seconds, with 99.99 percent accuracy to well below immediately dangerous to life or health (IDLH) levels, for several hundred compounds. Several manufacturers are close to reaching this goal; some devices should be ready in 2006.
The ability to integrate devices with both wired and wireless networks is another improvement. Although the integration is mostly for support at special or large-scale events, there are potential applications for the emergency response world. The monitoring of zones and perimeters is one application, as well as the value of continuous monitoring in the hot zone. Adding the ability to connect to a network also requires specialized knowledge to keep the devices functioning.
One device uses IMS as the basis for detection but uses Fourier transform algorithms to improve the device. FT-IMS uses Fourier transform algorithms to improve the signal processing functions performed during testing. Although complicated Fourier Transformation (FT) is a mathematical calculation. Most detection devices use a form of ionization to determine the type or category of material present. In many cases the devices are looking for a few key peaks in the resulting algorithms. The IMS portion of the device is based on how ionized chemicals separate under an electrical field. Different ions of size and strength separate, creating concentration peaks, or what could be called an algorithm. The FT portion of the device converts this signal to a complex spectrum, comparable to the spectrum produced by Fourier Transform Infrared Red (FTIR) devices. The devices have limited libraries to compare against the resulting algorithms and will have some identification issues. The use of the combined FT-IMS technology has allowed a dramatic increase in sensitivity and shorter reaction times. As with all of the detection devices, the key issue is accuracy. Obviously, any device that improves response time and sensitivity is a good thing, and the standard IMS devices are moving in the right direction.
Another technology that has seen some improvement is flame spectrophotometry, especially in the area of toxic industrial compounds, commonly referred to as TICs. The devices have not changed, but one manufacturer has a separate device just for TICs, which can be cumbersome. Current devices can detect up to 21 industrial materials, with some being more useful than others.
Simple chemical detection devices have recently hit the market for first responders. They can detect corrosives, phosgene, chlorine, sulfides, toluene diisocyante, and carbon monoxide. The individual sensors fit into an armband and can be switched out. One manufacturer is planning for six new sensors in the near future. The new sensors have three-month shelf lives at room temperature and twelve-month shelf lives while refrigerated. Once opened, they are good for 24 hours.
Similar devices can detect corrosives, chlorine, fluorides, nerve agents, oxidizers, arsenic, hydrogen sulfide, and cyanides, but have shelf lives of two years and operational times of 12 hours once opened. One manufacturer offers M-8 style paper in a detection card in addition to a water safety test card. The water testing card tests for coli from bacteria, lead, two common pesticides, nitrates, nitrites, chlorine, corrosiveness, and hardness. Make sure when you do your research that you are comparing apples with apples. The two test strips have comparable testing abilities but have major differences in shelf life and operational time. Knowing the thresholds of detection is a key factor in determining which test or device to purchase. One should compare the differences between the two devices and then make any purchases based on a side-by-side comparison.
RAMAN TECHNOLOGY
For haz-mat responders, use of Raman technology is picking up speed and is competition for Fourier Transform Infrared Red (FTIR) detection devices. Both are comparable in abilities, but the manufacturers of both are making changes to keep up with the competition. Raman technology uses a laser beam aimed at the chemical sample and measures the scattering photons. Each chemical has a varied ability to scatter its photons when a laser is used; most of the light is reflected back off the chemical, while some is absorbed. Some of the light excites the molecules in the sample and scatters. Some of the light excites the molecules in the sample and scatters the light. The excitation causes a vibration and re-emission of light at a differing optical frequency which can be measured and matched to chemicals loaded in the device’s library, much like a fingerprint.
FTIR units use an infrared light source to make the analysis and develop a chemical signature or fingerprint. Users should consider the number of materials the unit can detect. Both FTIR and Raman units can allow users to input their own materials. The advantage with the Raman units is their ability to detect materials through a clear container, although the sample has to be very close to the laser. Water and carbon dioxide do not have any effect on Raman, but they have a minimal effect with FTIR units. Even a slightly experienced FTIR user can eliminate these interfering materials. The FTIR units require that a small sample be placed on the detection surface, out of a container.
Both FTIR and Raman have two significant issues responders must keep in mind:
1 Neither is 100 percent accurate, and can miss some materials.
2 Neither device can differentiate mixtures. For example, the technology can miss 10 percent of a potential mixture in an unidentified material, e.g., a 10 percent mixture of a dangerous material in 90 percent safe material. In this instance, neither unit would detect the dangerous material.
In some cases, the percentage that the devices miss may be more than 10 percent. Although they are very valuable devices, the user must understand their limitations, and back up the street-level decisions with laboratory analysis.
Other technologies that involve mixing old and new technologies are on the way. In many cases, there is some miniaturization of older detection sensors, which allows the devices to have smaller footprints. Many of the new detectors are designed for biological threat agents, but some have chemical agent detection ability.
BIOLOGICAL DETECTION DEVICES
One biological detection device uses microfluidic separation technology for biological sampling. With this technology, a sample is added to the device, which has a series of tubes that can track the movement of the material. The length of time a material is retained in the tracks, or channels, determines its identification. As part of the process, a laser is used to look for the fluorescent dye added to the sample, which is detected on the other end of the sample channel. The basic function is much like a handheld assay and adds a sample to a buffer and dye solution, which tracks the movement of a sample down a track. If the target material is present, the dye is picked up on the other end typically by an electronic reader. This device allows for the detection of bio-toxins such as ricin, staphylococcal enterotoxin B, and botulinum toxin. In the future, developers want to be able to detect viruses and bacteria.
Several other competing technologies are emerging. One technology uses a handheld biosensor that reportedly detects live and dead bacteria, bacterial spores, toxins, RNA and DNA viruses, Rickettsia, and fungal spores. The list is pretty impressive for a small handheld detection device. The technology uses a suite of semi-selective sensors that quantify the number of organisms on the sensor surface. The array of sensors allows the device to use its multiple sensors to identify a particular material. Developers state that the device can be used for initial testing. The results are then used to identify what additional tests to conduct. Given the wide range of materials the device can potentially identify, there may be some issues with false positives. On the bright side, however, the fact that scientists have developed a small handheld biological detection device is very promising. It may take a few years before this technology comes to the first responder market.
OTHER EMERGING TECHNOLOGIES
Several universities and commercial entities are working on cantilever sensor systems that can detect a variety of chemical and biological substances. Another name for the technology is the Nanomechanical Olfactory Sensor, or NOSE for short. NOSE devices use a series of very tiny fibers coated with a material that has an affinity for the target substance. The variety of fibers can result in redundancy in the detection system. A number of groups are looking to employ this technology, which, given the size and ability to cross-reference other materials, has some potential as well. In the field of chemical detection, advances in gas chromatography have provided for a small handheld unit that can detect a wide variety of chemical substances. Current units have been successful in identifying chemical warfare agents. The devices use a very small chromatographic column in combination with a quartz crystal acoustical wave detection device, which can be used to discriminate among various substances. This combination of technologies also provides some redundancy and will hopefully allow the handheld device to be very accurate in a civilian setting.
There have also been a number of advances recently in WMD detection devices, and the outlook is very promising. The thresholds of detection are increasing, detection times are dropping, and the accuracies are improving. The devices that have been out for a while face new scrutiny by consumers and the federal government. Recent testing was completed by the Association of Analytical Communities (AOAC) on Hand Held Assays (HHAs) which can test for biological threat agents. The testing certified one company out of five during the testing process. The testing, conducted in cooperation with the Department of Homeland Security (DHS) and the Department of Defense (DOD), was an important first step. There have been further discussions, and these groups are working towards additional testing of a variety of devices. Hopefully, the next round of testing will involve polymerase chain reaction (PCR) testing devices, which have been developed by several companies. The use of PCR is an important step for first responders, as it is one of the tests conducted by the LRN labs, which were set up with the Centers for Disease Control and Prevention (CDC) and the FBI. If PCR units can prove themselves, it would be an important step in street-level testing. Comparing apples with apples is important with these units because more companies are selling units to first responders. Some can provide results in 10 minutes; others take more than 40 minutes. So far, no comprehensive testing has been done with these units to test their accuracy. The DOD tested one device and found that it had an accuracy rate of 85 percent, which the DOD was calling a new gold standard. One would hope that before first responders call a testing device a gold standard, the accuracy would be upwards of 99.99 percent.
SUMMARY
The technological changes coming will place more emphasis on training and education for the first responder. In some cases, we may need to step back and look closely at the role we have chosen for ourselves. Hopefully, the technology will be better designed for our needs, as opposed to the laboratory’s. Accuracy is still a significant issue. Although significant improvements have been made, first responders still do not have a handheld instantaneous reading biological threat agent detection device.
Some detection devices are easy to use and have minimal preparatory steps to provide the analysis, but others have too many complicated steps to extract results. Be careful what you buy, and do your homework. Ask lots of questions, and let the lowest common denominator in your station try to operate the device. Pay for or request as much training on the device as possible-don’t try to save some money by skipping the training. Doing so is doing a great disservice to your citizens. It is amazing how many responders will spend $20,000 on a device but skip the $1,000 training class. When the device breaks, or if the responders can’t make it operate, they blame the machine and never their lack of training. We must learn to trust these machines, as they have some very interesting capabilities; but they are machines and at some point the human must make some decisions. Use a risk-based strategy that combines different detection technologies. Remember, however, that you can never be 100 percent accurate-only the laboratory can make that grade. ●
● CHRISTOPHER HAWLEY, a 23-year of the fire service and a haz-mat responder for 16 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 is a retired fire specialist with the Baltimore County (MD) Fire Department, where he was 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 looking to purchase WMD detection devices, you want to buy the best device for your money. Don’t start by looking at devices; focus on the technology. Choose a detection technology (or combination) and then look at devices. Compare each device side by side, and then compare them using the items listed below. Some of the questions to consider when buying a detection device are
• 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 and, if so, how often must they be replaced?
• What is the cost of the disposable supplies?
• What maintenance does the unit require?
• How often must maintenance be performed, and what are the costs?
• What are the lower detection limits (for all materials – not just the main one)?
• What about false positives and false negatives?
• What are the temperature ranges for the device and any supplies?
• Can the test be saturated by a pure sample? If so, what happens?
• Is 24-hour technical support available? Specifically by whom: 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 has conducted the third-party testing of the device? Can you obtain a copy of the test results?
