Predicting Hazardous Materials Emergency Outcomes
Ludwig Benner
Chief, Hazardous Materials Safety Division, National Transportation Safety Board
Proceedings of
21-25 July 1975 San Diego CA
The prevention of accidents is one of the primary objectives in the safety field. These safety efforts fall short of perfection, so concern about the consequences in accidents is also widespread. In the field of hazardous materials manufacture, distribution and transportation, concern for the consequences of accidents is heightened, because the presence of hazardous materials in an emergency can escalate the losses to disaster proportions. For example, the accidental release of a flammable gas can create problems far beyond the immediate surroundings of the vehicle in a transportation accident, as observed in accidents at Decatur, Illinois; Meldrin, Georgia; and Berlin, New York, among others. In other circumstances, the involvement of hazardous materials can produce catastrophic consequences for the operators of a facility, as happened at Flixboro, or transport vehicles, as happened on the V.A. FOGG and in the crash of the Pan Am cargo aircraft at Boston's Logan airport.
Because of the behavior of hazardous materials in emergencies, such emergencies are of special concern to a wide variety of persons. It is of immediate concern to emergency personnel, who may be at the scene trying to cope with the behavior of the hazardous material. It is of concern to shippers, who introduce the materials into commerce, because of their desire to be "a good neighbor" as well as their liability when accidents occur. Transportation company employees have a direct interest in the handling of hazardous materials emergencies because they frequently suffer the injury and personal loss if the emergency is diagnosed incorrectly or if the response to the emergency is unsuccessful. Carrier management is concerned about the risk to all its employees, as well as the losses suffered by the firm when emergencies are not handled well. Trade associations representing segments of industry frequently prepare emergency guides or recommendations, and their interest is in the success of their efforts in subsequent emergencies. The public also has a direct interest in the handling of hazardous materials emergencies, in that it is frequently exposed to the danger unknowingly, and its expected reactions to the emergency is frequently unknown.
Preplanning for emergencies is a well recognized safety practice. The development of such plans depends upon the understanding of the behavior of of the elements involved in the emergency, and the formulation of steps which will fa~orably influence the course and outcome of the emergency. During this preplanning process, an expected scenario of events is intuitively developed and considered in the formulation of the proposed response actions.
In some fields, such as the nuclear safety field, the preparation of safety analysis reports that deal with accident outcomes is a specific requirement upon which granting of a license to build and operate a facility is predicated.
However, for most other activities involving hazardous materials, such requirements are non-existent. The facility owner will generally take steps to assure that the facility operates reliably and safely to protect his personnel and investment. Carriers, shippers, and others also try to consider emergency problems as a part of their safety program efforts. However the manner in which the hazardous materials involvement in the emergency is analyzed during these efforts varies widely. In these circumstances the quality of the results from these diverse methods also varies widely. To date, no systematic approach to the analysis of hazardous materials emergencies and their outcomes has been developed, by or for any of the organizations concerned with this problem area. Some encouraging work in analytical methodologies is underway, but it is in its infancy.
One of the most vexing problems with trying to develop a systematized analytical approach is the serious difficulties that arise while attempting to predict the behavior of hazardous materials in specific emergencies or accidents. Until the most likely course of events constituting the emergency has been predicted, the formulation and selection of the best response techniques to control the predicted behavior, and the well-managed execution of the action option selected are difficult - if not impossible - undertakings for the analyst or the operator.
Studies of the harmful effects of "incidents" have been conducted by the defense agencies, because they are interested in maximizing losses in such occurrences. The harmful effects of incidents involving commercial materials in emergencies also need to be studied, to determine how to minimize
the effects of such occurrences. The amount of effort devoted to the analysis of the behavior of hazardous materials in emergencies is limited. Probably the most extensive work has been perfonned in the development of planned process controls and protection systems in facilities where hazardous materials are produced. Little analysis effort has been expended in
the analysis of hazardous materials transportation emergencies. The Office of Hazardous Materials, to its credit, has issued an emergency guide for emergency personnel, covering some 30 chemicals out of the roughly 1,100 materials listed as dangerous in the Federal transportation regulations.
The Coast Guard has in the final stages of development a vulnerability model which addresses the behavior and effects of hazardous materials spilled in marine transportation. The speakers today will discuss other attempts and methods for analysis of such emergencies. However, the results of such analyses do not yet provide a basis for the promulgation of safety regulations, nor do they provide a basis for safety decisionmaking by the emergency response personnel, shippers, transportation company personnel,
governmental agencies, trade associations and the public. Among the results is a lack of understanding of the probable behavior of hazardous materials in emergencies, and in the absence of this understanding, resultant difficulties in dealing with emergencies when they occur, or developing appropriate preplans in emergency instructions or training.
The application of systems safety analysis methods in this problem area, to produce safer outcomes in hazardous materials emergencies, appears to hold promise. There are numerous systems safety analysis methods which might be adapted to this analysis problem. These methods include logic tree analysis, events logic charting techniques, failure mode and effects analysis, construction of scenarios of the operations research type, and decision analysis methods.
Methods for analyzing hazardous materials emergencies will be discussed by this panel, from the perspective of the different users. The formulation of the emergency response options will also be examined from their respective points of view. Problems encountered in the formulation of the action options for hazardous materials emergencies will be discussed by the panelists with emphasis on their perspective of the problem and the use to which their analyses are put.
As you observe or participate in this session, I ask you to keep in mind the purpose of the panel; it is to identify and to discuss methods used for the analysis of hazardous materials emergencies and predict their outcomes to meet the functional needs and requirements of the different users.