By Dan Kroll, Karl King, Terry Engelhardt, Mark Gibson, and Katy Craig, Hach Homeland Security Technologies
The vulnerability of our water supplies to disruption and contamination by potential terrorist or malicious acts has been well documented.1,2 These potential attack scenarios have the ability, if orchestrated successfully, to produce casualties on a massive scale. Studies conducted by personnel at Hach HST, Colorado State University and the U.S. Army Corps of Engineers among others have shown that attacks on drinking water supplies could be mounted for between $0.05 and $5.00 per death, using rudimentary techniques, and could amass casualties in the thousands over a period of hours.3,4,5
The most likely scenario for such an attack, in which the goal is to inflict mass casualties, is to orchestrate a simple backflow contamination event. A backflow attack occurs when a pump is used to overcome the pressure gradient that is present in the distribution system's pipes. This is usually around 80 lbs/in2 and can be easily achieved by using pumps available for rent or purchase at most home improvement stores or through internet sources. After the pressure gradient present in the system has been overcome and a contaminant introduced, siphoning effects act to pull the contaminant into the flowing system. Once the contaminant is present in the pipes, the normal movement of water in the system acts to disseminate the contaminant throughout the network effecting areas surrounding the introduction point. The introduction point can be anywhere in the system such as a fire hydrant, commercial building or residence. See figure 1.
|Fig. 1 All systems are vulnerable to backflow attack.|
The occurrence of back flow scenarios is not just conjecture. Backflows occur via accident on a regular basis and are of great concern to the water industry. In fact there is an organization, The American Backflow Prevention Association, dedicated to the study of and prevention of backflow events. Accidental backflow events have been found to be responsible for many incidents of water borne illness and even death in the United States. According to the USEPA, backflow events caused 57 disease outbreaks and 9734 cases of water borne disease between 1981 and 1998.6
To prevent such accidental backflows, many systems have been equipped with backflow prevention devices. A backflow prevention device is a means or mechanism to prevent backflow. These means of preventing backflow are very useful in preventing the all too common accidental event, but it should be noted that these devices are installed to prevent accidental backflows. They are all physical devices that can be removed or disabled quite easily by a would be terrorist thus, rendering them ineffective in preventing deliberate attempts at contamination by all but the most amateurish perpetrators.
Intentional dissemination of contaminants through a backflow event is in fact a very critical vulnerability. Studies conducted by the U.S. Air Force and Colorado State University have shown this to be a highly effective means of contaminating a system.7 These studies show a few gallons of highly toxic material was enough, if injected at a strategic location via the proper method, to contaminate an entire system supplying a population of 100,000 people in a matter of a few hours. Material and significant contamination was not relegated to only the areas surrounding the introduction point. Material flowed through each neighborhood and then reentered main trunk lines, thus, making its way to the next area until the contaminant had permeated the entire system. Using computer simulations, when a military nerve agent material was used over 20% of the population was determined to have received a dose adequate to result in death and when a common chemical was used in place of the warfare agent the result was a casualty rate of over 10%. Thousands of deaths could result from this very inexpensive and low-tech mode of attack. There is no doubt that this form of assault meets all of the terrorist's criteria for an attack. It would cause mass casualties, be inexpensive, and actually offer the terrorists a good chance of avoiding apprehension. Unfortunately, because monitoring for contamination in the distribution system typically is limited to infrequent grab samples, the first indications of such an attack are likely to be casualties showing up at local hospitals. A terrorist could launch such an attack and be on a plane out of the country before the first casualty is reported.
These sorts of attacks can occur from any access point to the water system. Wherever water can be drawn out, material can be forced back into the system. Some areas, however, are more vulnerable than others. Access points near high flow areas and larger pipes would be favored because they would disseminate the material to a wider area more quickly, however, any access point except for those at the very end of long deadhead lines could be used to effectively access the system.
It should be obvious from the large number of accidental backflows that occur and the fact that terrorist organizations have shown an interest in attacking water, the distribution system is a prime candidate for such an attack. The fact is a bona fide terrorist is virtually inundated by possible candidate substances and locations that would be very effective in such a role. The possibilities are virtually endless. Protecting against and/or detecting such an attack is difficult.
Recent breakthroughs in the online detection of contaminants have made the deployment of a cost effective early warning system capable of detecting and categorizing such events a reality. The simple truth is that these systems are not widely deployed and, in locations where they are, the ubiquitous nature of potential attack sites makes 100% coverage of the population an effective impossibility until such time as it becomes practical to deploy sensors on every tap.
The Nature of a Potential Water Attack Necessitates Public Disclosure
Due to the nature to this sort of attack (easily orchestrated, capable of causing mass casualties, no physical means of prevention, early attack detection systems not universally deployed nor capable of 100% protection of the entire populace) it is imperative to realize that if such an attack occurs, casualties will be inevitable. As it becomes obvious that actions taken by utilities or the government are not capable of completely mitigating this threat to consumers, it becomes critical that the public be made aware of this potential threat and educated as to what actions should be taken if such an event occurs.
Education as to the nature of a potential threat empowers people at risk to take actions to reduce loss from potential hazards. Education accompanied by suitable public warning in the case of a detected event save lives, reduces fear, and speeds recovery. The success of an education and early warning program is measured by the actions people take.
Warning and education are an important element of providing for public safety. Public safety is a fundamental duty of municipal, county and tribal government and, for larger hazards such as a mass casualty water attack, state and Federal government. Public safety is also the responsibility of citizens to take action not only to protect themselves and their; loved ones, but also to make society safer through their jobs and community activity.8 This responsibility cannot be met unless proper education of the public is implemented so that they understand risks and can take appropriate action to ameliorate them.
A rational approach to the dilemmas presented by the occurrence of an intentional water contamination event will require the informed consent of a well apprised public, which in turn depends upon education. First responders and other personnel critical to the discovery of, mitigation and recovery from such an attack on municipal water supplies should receive education pertaining to the potential threat. This could be done through the development, by organs of the Federal government or their contactors, of a self-education Web site that emergency workers, water works personnel, police and firemen would be encouraged to visit. Many emergency workers, hospital; staff, National Guard personnel, and others whose decisions would be critical to the overall response effort in such an emergency are highly motivated to carry out their professional tasks and accustomed to continuing professional education and self training. Many of these individuals are likely to make use of such a training website especially if accreditation for continuing education could be provided.9
A second target for education on the threat, consequences, and appropriate action to be taken if such an attack were to occur would be the media. Many national and local media have one or more reporters whom cover terrorism, homeland security, and disaster response. If they were to be educated in advance regarding intentional water contamination events, they might be able to interpret the actions and advisories of public authorities for the public.9
A more difficult problem is posed by the pubic at large. The public is not liable to be acutely interested nor engaged until after an attack has occurred. It is nonetheless crucial that the government invest more resources toward educating local community leaders about immediate actions that can be taken in the aftermath of such an attack. Well-trained public officials operating from a response plan that has taken into account the potential for such a water emergency and communicating through a press corps that contains knowledgeable members is the best hope for informed choices by the public.9 Although a difficult proposition, any educational effort to inform the public pre-event will be sure to reap rewards, even if only a small subpopulation is reached. An informed public can result in a variety of benefits.
The Multiple Benefits of Public Disclosure
A well-informed public is an asset in that they are less likely to panic in the case of an emergency. A thorough understanding of the risks entailed in a water contamination emergency will result in a rapid and correct response by those that will have to deal directly with the results, a.k.a. consumers. Besides the obvious salutary effects of being able to limit exposure, preventing panic and hastening clean-up and recovery there is an added benefit in having an informed public in the case of water contamination emergencies that doesn't exist for other types of terrorist attack and natural disasters. Hurricanes and nuclear detonations are by their very nature not difficult to detect. A water emergency, on-the-other-hand, may not be readily apparent. An informed public may be able to help in the discovery of such an event.
It is wise to request help from the public in spotting any unusual activity that may be associated with terrorist activities related to the water supply. Active programs of soliciting the public's support are always a good idea. Some utilities have actually personally recruited and educated people whom live near key areas to help keep an eye on them. The public should be kept informed of what to look for and how and where to report suspicious activities. Posters in key locations and hints on what to look for and how to report included in billing statements or other communications are a good idea as are recurring articles in local publications and other media outlets.
The public often asks what they should be looking for. The blank statement of anything out of the ordinary is often used to offer guidance in these situations. Often this is not enough but should be followed with specific examples of behaviors to look for and details about the potential threats. In general there are indicators that can be used to recognize potential terrorist groups and potential terrorist probing, surveillance or pre-attack activities.
According to the USEPA examples of suspicious activities specifically related to water incidents that should be reported might include but are not limited to:10
1) People dumping or discharging material to water sources.
2) People climbing or cutting a utility fence.
3) Unidentified truck or car parked or loitering near a waterway or facilities for no apparent reason.
4) Suspicious opening or tampering with manhole covers, buildings, or equipment.
5) People climbing on top of water tanks.
6) People photographing or videotaping utility facilities, structures or equipment.
7) Strangers hanging around locks or gates.
8) Vehicles other than fire trucks hooked up to hydrants.
Consumers should also be encouraged to report any taste and odor problems. While consumer complaints are a valuable source of information, they should not be overly relied upon to detect problems. Many chemicals and biotoxins are not detectable by the consumer because they have no taste or odor. It would also be prudent to ask industrial suppliers, home improvement centers and hardware stores to report unusual purchases of high-pressure pumps and large mounts of industrial chemicals, herbicides or pesticides.
When reporting incidents people should be advised not to confront the suspicious individuals, but rather report it. Some important information people should include is:10
1) Nature of the incident.
2) Your identity and location
3) Location of activity
4) Description of any vehicle involved (color, make, model, plate #)
5) Description of suspicious individuals (how many, sex, race, color of hair, height, weight, clothing, etc.)
While relying on civilian input to report incidents may be an important component of detection for some parts of the system, it should be noted that the average person is not a trained observer and are liable to not notice or be shy about reporting incidents. Studies have been conducted since 9/11 where unmarked trucks with middle eastern individuals were hooking up to fire hydrants to see if anyone would report the unusual activity. No one did!!!!! Obviously, while helpful, reliance on public reporting should not take the place of other types of monitoring.
In the aftermath of 9/11, the then EPA administrator Christie Whitman said:
"People are worried that a small amount of some chemical or biological agent -- a few drops for instance -- could result in significant threats to the health of large numbers of people. I want to assure people -- that scenario can't happen. It would take large amounts to threaten the safety of a city water system. We believe it would be very difficult for anyone to introduce the quantities needed to contaminate an entire system."
Statements such as these made by officials result in a false sense of security. The fact is that our water supplies are vulnerable and there is nothing that we can do in the near future to 100% assuage the risk.
Offering the public platitudes will do no one any good. A well-informed citizenry is the ballast that will maintain society in a steady state in the aftermath of any potential emergency whether that emergency is the result of water contamination, other terrorist activity or a natural disaster. Not only will it reduce the potential destructive nature of any of these events but also in the case of water contamination emergencies, may actually aid in the early detection of such an illicit action. It is the public's right to be fully informed and, it is our duty to see that it is done in such a way as to optimize the potential benefits while preventing paranoia or general mistrust of water supplies.
1) Kroll, Dan. 2006. "Securing Our Water Supply: Protecting a Vulnerable Resource." PennWell Publishers. Tulsa, Oklahoma.
2) Hickman, Donald C. 1999. "A chemical and biological warfare threat: USAF water systems at risk." Counter Proliferation paper No. 3. USAF Counter Proliferation Center, Air War College.
3) Kroll, Dan. 2003. "Mass Casualties on a Budget." Confidential Briefing Paper. Hach HST.
4) U.S. Army Corps of Engineers. n.d. "Calculations on threat agents and requirements and logistics for mounting a successful backflow attack."
5) Allman, T.P. 2003. "Drinking water distribution system modeling for predicting the impact and detection of intentional contamination." Master's Thesis. Department of Civil Engineering. Colorado State University.
6) USEPA 2002. "Potential Contamination Due to Cross-Connections and Backflow and the Associated Health Risks: An Issue Paper." www.eap.gov/ogwdw/tcr/pdf/ccrwhite.pdf
7) Allman, Timothy and Kenneth Carlson. January 2005. "Modeling Intentional Distribution System Contamination and Detection." Journal of the American Water Works Association. Note: The executive summary of this article is still available online but the full text has been pulled from the AWWA website for security reasons.
8) Partnership for Public Warning. "A National Strategy for Integrated Public Warning Policy and Capability." May 16, 2003.
9) Carter A. B., May, M. M. and Perry, W. J. "The Day After: Action Following a Nuclear Blast in a U.S. City." The Washington Quarterly. Autumn 2007.
10) EPA. "Water Security and You." http://cfpub.epa.gov/safewater/watersecurity/pubs/water-security-article.pdf
WaterWorld Online, March 2010