Experts systems to assist first responders to chemical emergencies

Expert Systems WithApplications, Vol.2, pp. 129-135,1991

0957-4174/91 $3.00+ .00 © 1991PergamonPressplc

Printedin the USA.

Expert Systems to Assist First Responders to Chemical Emergencies JUDITH M. H U S H O N ERM-Program ManagementCompany, McLean, VA

Abstract--Response to emergency situations involving chemicals requires an understanding of the physical and toxic properties of the materials involved, how these materials interact with each other and the environment, and how to remediate the situation. This response, to be maximally effective, must be rapid and properly focused. This puts a burden of both speed and accuracy on the responders who often lack specialized training in toxicology or environmental chemistry. Expert systems are an ideal way to provide these first responders with access to this type of expert level advice on an as needed basis. This article focuses on why expert systems are appropriate tools for emergency response and defines the scope of several of them including." TSDSYS, LABSYS, HASP, FRES, and HERMES. Each of these tools fulfills a separate need. TSDSYS helps the user select and identify vendors of treatment, storage, and disposal options while L A B S Y S assists in the selection of environmental analytical testing laboratories. HASP assists in the generation of site and activity specific health and safety plans that are required before personnel can enter an emergency site. F R E S and H E R M E S are designed to provide support to first responders to chemical emergencies and rely on complex algorithms to provide guidance in a wide range of required areas.

1. I N T R O D U C T I O N CHEMICAL EMERGENCIES OCCUR in the U.S. at the rate of about 30 per day (Anon, 1985). Most incidents are handled by local firefighters. However, the Superfund Amendments and Reauthorization Act (SARA) calls for EPA to become involved in larger scale incidents and in those requiring more technical knowledge. As a result, the EPA plays an active role in about a thousand emergency response incidents per year. Having accurate information available on the extent of the threat posed by the chemical involved in the incident and on precautionary measures that should be taken can improve the response efforts for both small and large responses. However, it often becomes more critical in the larger incidents because more persons are potentially involved and greater property damage is possible. The following is an example of an incident that might have turned out differently had chemical information been available and used by the firefighters. A fire was reported at Cyclo Corporation in Miami, FL at 8:30 PM on March 28, 1987. The firefighters arrived promptly and immediately responded by pouring water on the fire. This water reacted with chlorosulfonic acid present at the facility and caused an explosion that

killed one firefighter and injured 33 others. Had these firefighters been aware of the properties of this chemical, they would have reacted differently. Systems that support emergency response must provide their assistance to the user rapidly and the information must be highly focused since the responders have little time to read through lengthy text. Effective emergency response also involves knowledge of toxicology, environmental chemistry, and environmental engineering, just to name a few of the disciplines. Knowledge from these disciplines is not included in standard training programs for firefighters who make up 94 percent of the U.S. first responders (Robinson, 1987). Expert systems for incident response use knowledge bases of chemical property and emergency procedures plus rules about how to interpret this information for solving emergency response problems. Only a few expert systems have been implemented to support emergency response (Hushon, 1987). Some are highly focused on addressing a particular subproblem while others are more broad-based in their approach. Five expert systems will be discussed in this study. Three ofthem--TSDSYS, LABSYS, and HASP--were sponsored by the EPA. The fourth, FRES (First Responder's Expert System), was developed and marketed by Roy F. Weston, Inc. The remaining system, HERMES, was developed by the Alberta Research Council, Calgary, Alberta, Canada.

Requests for reprints should be sent to Judith M. Hushon, Ph.D.,

ERM-Program Management Company, 7926 Jones Branch Drive, Suite 210, McLean, VA 22102. 129

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Z M. Hushon

2. TSDSYS ( T R E A T M E N T STORAGE AND D I S P O S A L SYSTEM) The purpose of this system is to assist the EPA Technical Assistance Teams (TATs) to identify appropriate treatment, storage, and disposal (TSD) contractors who specialize in waste site remediation. This process is complicated by the facts that: (l) selection often must be done rapidly and (2) the government requires the submission of three bids so multiple contacts are generally necessary. The system is menu-driven and is designed to be operated by scientific and technical personnel. The data required as input into the system are the type of waste and the potential pollutant chemicals involved. Additionally, the geographic location of the TSD contractor may be important, if they are searching for an onsite treatment/disposal method. These required input data can be entered rapidly by persons familiar with the site and the waste. The system then provides a short summary of information on each vendor meeting the search criteria; this information is adequate for making a telephone contact. Alternatively, more detailed listings can be requested that provide more in depth information about the particular technology (see Exhibit 1). TSDSYS was initially designed using the KES tr) shell by Software A&E for operation on the PC/AT class machines used by EPA response personnel. It was quickly recognized, however, that maintenance of the file on multiple, widely distributed machines was going to be a problem. This difficulty arose because the database requires updating three times per year to maintain its currency. Distributing these updates and ensuring that they were installed on the proper machines was going to be difficult. The decision was then made to reprogram the application in DM(r) to operate on Weston's VAX 8350; the TAT staffwere given Crosstalk(r) script files to accomplish the dial-up and login transparently. The interaction then looked identical to that on the PC. An expert system approach was taken to developing this system because the problem structure lent itself well to that paradigm. The system design was accomplished through a number of group sessions during which the knowledge engineer queried the experts on the information they required to make their decisions. Later sessions were devoted to evaluating prototypes developed by the knowledge engineer and modifying the logic as required to bring it into line with the expert's expectations. A database of information on a number of treatment, storage, and disposal technology options and the vendors of these options was also designed and built. The data for inclusion in the system came from EPA reports, practical experience, and service directories.

When the decision was made to move the system from the PC to the VAX 8350, it was decided to develop the system in DM tr) to avoid having to invest in additional expert shell licenses. DM worked well for the database management functions and was able to be programmed to use rule-based, forward-chaining logic as well. Because the PC based system was developed first, it could serve as the model for later development. This system has been in successful operation for almost 3 years. It is available for commercial access as well as for use by EPA. 3. LABSYS (LABORATORY SYSTEM) LABSYS provides support to the same group of individuals as TSDSYS, the EPA Technical Assistance Teams. The difference is that LABSYS displays information on laboratories that are capable of analyzing samples of environmental media to determine their degree of contamination. Laboratory analysis of environmental samples is often required before a remedial option can be identified; thus it must be accomplished as rapidly and efficiently as possible. Laboratories must be selected that have the appropriate certifications, can handle the anticipated sample volume, and can meet additional requirements for rapid turnaround or mobile facilities, if necessary. In addition, as with TSDSYS, three laboratories must be contacted to provide quotations so multiple appropriate facilities must be identified. Like TSDSYS, LABSYS resides on the VAX 8350 and was written in DM. LABSYS is also menu driven, but the required information is different: medium of sample, number of samples, suspected pollutants, and location. In addition, the program is capable of taking requests for mobile laboratories and for rapid turnaround into consideration. The output is a listing of laboratories that met the user's criteria and the possibility of obtaining more detailed information on the numbers of various pieces of equipment, for example. The contents of the system were identified by a group of those TATs currently charged with performing this task. The system was then designed as a prototype and the "experts" asked to critique it and make suggestions. The information in the knowledge base was collected by a direct survey of analytical contract laboratories; this system is updated semi-annually. LABSYS has been in use for almost 2 years and is also available for commercial use. 4. H A S P ( H E A L T H AND SAFETY PLANNER) EPA personnel cannot enter an emergency site until an incident specific health and safety plan has been prepared and approved by the Site Health and Safety

131

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Officer. This plan identifies the appropriate level of protective clothing for the pollutants present and the activities to be performed, and provides important information about the potential hazards posed by the chemicals present. The health and safety plan also contains a considerable amount of "boiler plate" text from which appropriate sections must be selected and edited. An expert system can greatly facilitate HASP preparation by automating this text selection process;

in addition, it is possible to have plans prepared by persons other than Health and Safety Officers, though the Health and Safety Officers do have to review and approve all plans. HASP is an expert system written in KnowledgePro(r) to operate on a Compac (° portable, the machine of choice for EPA field work (Hushon & O'Neill, 1990). This program accesses databases containing chemical information that was derived predominately from the

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RIDS file of CAMEO, ] O H M T A D S , 2 the EPA guidance on suit materials, and NIOSH Sampling Methods. All of these databases are in the public domain. The desired information was extracted from these databases and organized into dBase files which HASP accesses. This program takes advantage of both the expert system and the hypertext capabilities of the KnowledgePro software. The expert system portion of the code was designed to ask a user what types of activities he expected to undertake and the probable chemicals involved including approximate concentrations, if known. The program then determines the appropriate suit level, suit materials, protective ensemble, and N I O S H sampling method and prepares the report. The user can override the generally conservative program, but must enter a reason and this action is flagged for the Site Health and Safety Officer during his/her review. Figure 1 shows a sample HASP screen. The Knowledge-Pro hypertext functions are used mainly to provide explanations of terms used in health and safety plans and to provide context specific help. The knowledge and heuristics in HASP came from experienced EPA and Weston Health and Safety Ofricers associated with the REAC program in Edison, NJ. The process used to elicit this information involved i CAMEO is an emergencyresponse support computer system that uses hypertext capabilities to make stored chemical information available. It has a cartographic base. CAMEO contains a file called RIDS that contains factual information on over 2600 chemicals. CAMEO is not an expert system. 20HMTADS is an online computer file originally constructed by EPA, but now vended publicly that contains factual and numeric information on approximately 1000 common chemicals.

the creation of prototypes of parts of the system by the knowledge engineers with critiqueing provided by the experts. The experts were also given truth tables to complete and levels of risk to identify. The decision was made to have the system be conservative. The standardized text of the health and safety plan has been agreed to by EPA. The expert system is now in the third and most extensive round of field testing by TATs and REAC. Broader distribution is planned to EPA and its contractors in 1990.

5. FRES ( F I R S T R E S P O N D E R S '

EXPERT SYSTEM) This system is designed to be used during an incident to provide expert level guidance to first responders or for use in training of first responders. Expert system technology was appropriate for this application, because multiple types of expertise are required to respond to an emergency involving chemicals. For example, toxicologists and environmental chemists are rarely available at an incident site so FRES provides the access to alternate sources of this expertise (Hushon, 1988). FRES first asks the user to respond to a series of questions (the exact number of which will vary depending on the situation) about the incident. These questions seek answers about the materials involved, whether there is evidence of fire, and the area in which the incident occurred. Based on the responses, the system develops an appropriate response strategy. The system considers the following:

ES for First Responders • selection of appropriate clothing for fire fighting or spill cleanup, • decontamination procedures, • estimation of likelihood of exposure, • interchemical reactivities, • combustion products and their hazard, • flammability limits, • fire extinguishing methods, • need for evacuation and number of persons likely to require evacuation, • impact of local weather conditions on the situation (autoignition, explosion, vaporization), • whether substances will react with surface water, • whether spill represents a threat to surface water supplies, • spill cleanup methods, • symptoms of exposure, • first aid measures, and • acute toxicity level by different routes of exposure. The database of this system contains detailed information about a variety of chemicals that are involved in incidents. The response provided to the user is tailored to the chemicals and the incident. This represents the main difference between expert systems and traditional MIS approaches to emergency response information management (e.g., handbooks, online databases such as HSDB, 3 0 H M T A D S , or HAZARDLINE, 4 or other PC-based tools such as CAMEO). Despite the fact that the FRES system functions at an expert level and numerical/factual data about the chemicals are included in the system's database, the outputs provided to the end users are presented in language that a firefighter can understand. For example, instead of reporting that the vapor density is 1.87, the system informs the user that "the chemical is heavier than air and may collect in low lying areas." Similarly, toxicity data are translated into meaningful terms. One major advantage of this system is that chemical interactions are taken into account. The system provides the user with information as to what materials interact as well as the type of interaction (e.g., explosion, release of toxic gas). FRES also considers reactions with other materials possibly present at the site such as dust and water. This system was originally built using KES on a PC/ AT with 640K RAM with the chemical database constructed in dBase. When the chemical database was expanded, a dBase front end was added that provided for the collection of the initial information on the incident. This is done in a question and answer format 3The Hazardous Substances Data Bank (HSDB) is a peer-reviewed database that contains textual information on over 5,000 chemical substances. This database is maintained by the National Libraryof Medicine on their TOXNET system. 4 Hazardlineis a textual chemicaldatabase that is marketed by OHS and is offeredby severalcommercial,online, computer system vendors.

133 with optional answers provided for user selection. The dBase front end was added because the KES shell did not support the ability to select from among multiple chemicals without listing them on a screen and then asking the user to select from among those offered. This was fine for a test set, but not for a functional, fully loaded system. FRES was subjected to an elaborate field test using a methodology originally developed by Yu et al. (1979) for MYCIN. Four sample incidents were prepared by an outside expert with many years of experience in chemical incident response. Each incident consisted of a problem and a series of questions. Each incident was given to 10 responders and the expert system. The responders were selected so that they represented a range of response experience and training from rookies to persons with 20 years of experience. The results showed that the system was as good as the expert responders on two of the incidents, and better than all of the responders on the other two (Hushon, 1988). This was a very positive response for the areas in which FRES did not perform well were in ordering response options and in identifying who should undertake certain tasks, items for which it had purposely not been programmed. FRES has been used in a number o f incident response simulations, but it remains a prototype for lack of a larger, standardized, factual/numeric database of data. At the present time, there are 21 materials commonly involved in incidents in its database. 6. H E R M E S ( H E U R I S T I C E M E R G E N C Y RESPONSE MANAGEMENT EXPERT SYSTEM) HERMES development was undertaken as a joint project by the Alberta Research Council, Alberta Public Safety Services and Emergency Preparedness Canada. A prototype has been developed in mu-LIS1~r) on a Symbolics machine running the ART ¢r) expert system shell (Chang, Clark, & Sidebottom, 1988). HERMES, like FRES, is designed to assist emergency response personnel in the management of accident situations involving dangerous materials. Users are asked to enter information on the nature of the accident such as the materials involved, the rate and volume of leakage, and so forth, as well as environmental variables such as the proximity to population centers and weather conditions. The system then estimates hazard levels such as fire and explosion risks and recommends procedures to follow for containment or evacuation. One of the most unique features of HERMES is its graphical user interface which features a variety of window selections that can be changed by the user at any time. They can be used to update the situation and will, if appropriate, result in changes in the system recommendations (see Fig. 2). The system provides

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graphical representations of the evacuation distance, the general danger of the situation, the danger of explosion, the danger of fire, site danger, public danger, worker danger, and danger to the environment. The system also recommends emergency actions and asks to be kept informed of actions that have been taken at the site. Likewise, if site conditions change, for example, it starts to rain or the wind direction changes, this will affect both the danger levels and the recommended actions. This system currently exists as a prototype that can be used for incident response and for emergency responder training. Because of the hardware platform on which it is built, this system is designed to reside at a central location by a dispatcher who is monitoring the emergency situation. The system's recommendations must be relayed verbally to the scene of the incident.

7. LIABILITY Because emergency response expert systems may affect life and death decisions during an incident response, they carry with them a certain implied liability. The developers of these expert systems are concerned about

the whole issue of liability, but no attempt has yet been made to determine whether this concern is warranted. According to the Brookings Institution, the number of product liability lawsuits has increased eight-fold from 1974 to 1986 when 13,595 such cases were filed (Warner, 1988). However, in the expert systems area, no suit has yet been filed. Some system developers are attempting to limit their responsibility by including disclaimers, but lawyers say these may offer little refuge because buyers rarely return license agreement cards. Lawyers have suggested that systems which leave the final decision up to the user will have reduced liability. This is generally the approach taken by the emergency response systems since it is impossible for them to take into account all possible situations and response options. Liability may also depend upon whether there is a "bug" in the software; no software company has yet lost a lawsuit brought over a bug though there have been several out of court settlements. One final claim used by developers is that expert systems represent an inexact science. There are also efforts underway that are focused on reducing the total liability to software developers by avoiding excessive awards and introducing a no-fault

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claims system which may be of future benefit (Ruby, 1986). These concerns have definitely slowed development of emergency response expert systems. This may lead to only developing prototypes which never become production systems. Another result is that much of the existing development has had government cooperation in an attempt to limit liability by the private developer.

8. CONCLUSION These expert systems assist first responders with various tasks associated with chemical incident response. The first three systems all are designed to tackle small parts of the emergency response problem, while the two larger systems discussed at the end try to provide a more comprehensive support directly for the responders. These larger systems are much more difficult to develop and require much more effort to validate them for use in actual situations, because of the potential liability involved.

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REFERENCES Anon (1985). Statistics on toxic chemical accidents compiled. Chemical and Engineering News, October 14, 7, Chang, E., Clark, D., & Sidebottom, G. (1988). Heuristic emergency response management expert system. In Proceedings of the Fifth Technical Seminar on Chemical Spills. Montreal, Quebec, 323335. Hushon, J. (1987). Response to chemical emergencies. Environmental Science and Technology, 20(2), 118-121. Hushon, J. (1988). The feasibility of using an expert system to assist first responders to chemical emergencies (Ph.D. Thesis). George Washington University, School of Government and Business Administration. Hushon, J., & O'Neill, M. (in press). Health and Safety Planning Expert System. In J. Hushon (ed.), Expert systems for environmental applications. American Chemical Society Symposium Series 431. Robinson, J., Interview with Chief of the Seattle Fire Department, Seattle, Washington (April 13, 1987). Ruby, D. The software industry could face the specter of liability lawsuits. PC Week, July 8, 1986, 49. Warner, E. (1988). Expert systems and the law. High Technology Business, 8(10), 32-36. Yu, V.L., Fagan, L.M., Wraith, S.M., Clancy, W.J., Scott, A.C., Hannigan, J., Bium, R.L., Buchanan, B.G., & Cohen, S.N. (1979). Antimicrobial selection by a computer. Journal of the American Medical Association, 242(12), 1279-1282.