This article was submitted to the Environmental Safety & Health Communication Professional Interest Committee Newsletter Editor, Dr. Hillary Hart, University of Texas at Austin, Fall 1997. As the article suggests, it was in response to an article in the Spring 1997 issue that argued against using risk assessment in environmental management.

In the Spring, 1997 edition of the ES&H News there was an article by Peter Montague entitled " Making Good Decisions without Risk Assessment". This article was a critical view of risk assessment that not only stated that "risk assessment as usually practiced is unethical," but further suggested that risk assessment is generally manipulated to support a bad decisions. Mr. Montague’s comments are symptomatic of the lack of understanding of the science and process of risk assessment and further emphasizes the need for more formal training in risk assessment methods and risk communication. It is unfortunate that Mr. Montague is not aware of the many new advances in risk science and the importance of risk-based decisions in almost every aspect of life today. We would like to expand on Mr. Montague’s statement that "risk assessment could be applied to each alternative, as one part of a decision-making process." This is an important concession on his part and is the fundamental value of risk assessment.

Risk assessment is not a new concept and is not limited to environmental issues. In fact, most decisions we make on a day-to-day basis are, in part, based on an evaluation of the potential risks associated with that decision. For example, consider your days as a college student with a major exam the following morning. Your friends call and ask you to go to a party with them. The decision to stay home and study or go out and party with your friends the night before a big test could directly impact your ability to obtain a passing grade. To make that decision you evaluate your options by identifying the potential adverse effects for each option and weighing them against the benefits. An important point to emphasize in this decision is that there is a risk regardless of which option you select. If you stay home to study you risk missing out on a good time or possibly offending your friends. If you go out you may not do very well on the test the next day. Your decision must incorporate issues such as how well you know the subject to be covered on the test, how important the grade on this test is to your overall grade in the course or how important it may be to be with your friends. Once you have made your decision you have accepted the risks associated with that decision.

Environmental risk is defined as an analysis of the potential for adverse effects caused by an exposure to a chemical released to the environment. The process of quantifying the environmental risk resulting from an exposure to a chemical released to the environment is environmental risk assessment. It is the merging of many disciplines of science.

As an example, an exposure will occur when an individual comes in contact with the chemical through such mechanisms as inhalation of chemical vapors, ingestion of the chemical or contact of the chemical with the skin. The risk related to the exposure is quantified by applying data that have been collected regarding the potential toxicity or potential for adverse effects of a chemical. Where there is no current or potential exposure to a chemical or where the concentration of the chemical is not harmful to human health or the environment then the conclusion of the risk assessment is that there is no environmental risk or the risk is very small.

An environmental risk-based decision is the integration of risk assessment into the evaluation of alternatives to determine the potential harm associated with the release of a chemical into the environment. This decision-making process could be in the context of corrective action for historical releases (i.e., improving environmental quality) or in a prospective context of evaluating various alternatives for an industrial or commercial process (i.e., sustainable development). Regardless of the specifics of the application, There are several fundamental steps that are critical to the risk-based decision process. These activities are:

A critical element in making risk-based decisions is ensuring that stakeholders have an understanding of the process and the basis for the risk-based decisions. Stakeholder reaction to the potential for an environmental risk is an important consideration in making risk-based decisions. Stakeholders are individuals or groups that have an interest in or are potentially impacted by the outcomes of the risk-based decision process. Stakeholders include the community that is affected by a decision, the local and state government, the landowners involved, and the businesses involved. It should also be recognized that some decisions may affect communities other than the community immediately adjacent to the area of the actual or potential chemical release. To the extent that another community may be affected by a decision, that community should also be included as stakeholders in the process.

For any past (e.g., corrective action for a historical release) or future release (e.g., installation of a new industrial facility or waste management facility) of a chemical there will be alternatives for solving or addressing the release. Each alternative will have characteristics that define its benefits to the stakeholders and its risks. It must be recognized that the risks associated with an alternative are not just limited to human health risks but also include other non-environmental risks such as financial risks. The important point to remember is that all of the alternatives will have some potential benefit but will also pose some potential risk. The science of risk assessment helps stakeholders quantify the potential risks of each alternative and allow for the rational, objective comparison of the alternatives.

Environmental risk-based decisions require the consideration of a combination of scientific, social, political, personal and economic factors. These factors must be incorporated into the risk management decisions. The risk management decisions are necessary to support determinations that are protective of human health and the environment. Risk management decisions are the "ground rules" for risk-based decisions within which the science is conducted. Essentially, the risk management decisions provide a means for similar decisions to be made for similar circumstances while allowing the consideration of issue-specific circumstances and provide the basis for defining acceptable environmental risk. Determination of a consistent set of risk management decisions provides a basis for the objective comparison of alternatives. Clearly, a risk-based decision cannot be made without having access to these risk management decisions.

Many risk management decisions rely on the application of scientific methodologies for definition. For example, identification of chemicals of concern, determination of acceptable concentrations of chemicals and determination of appropriate data quality and quantity are risk management decisions that depend on science. However, other risk management decisions rely on non-scientific factors for definition. For example, the determination of future land use, point(s) of exposure, and acceptable incremental lifetime cancer risk factors are risk management decisions that are based social, economic or other non-scientific factors.

A variety of technical, social and psychological issues are related to chemicals that could pose a hazard and the public reaction to use of risk-based decision making to address that potential hazard. Determination of the risk management decisions prior to implementation of the risk-based process and discussion of the range of options for these decisions among the stakeholders involved in the environmental issue at hand will necessarily incorporate the views and values of the stakeholders in the decision-making.

Good decisions require good information. Therefore, an essential activity in risk-based decision making is to collect the information and data necessary to identify and evaluate the alternatives and to make reliable decisions. This not only includes technical data such as sampling and analysis of air, soil or ground water, and evaluation of the potential future scenarios in which a release might occur, but also includes information related to the area or community that is likely to be impacted by the alternatives considered and the information necessary to quantify the potential benefits to the community for each of the alternatives evaluated.

The process of making a risk-based decision applies the risk management decisions to each alternative to determine the potential for exposure to the relevant chemicals and to quantify the risks. The potential for exposure will be dependent on the exposure pathway, or the course a chemical takes from the point of a release to the point of exposure. An understanding and knowledge of the fate and transport of a chemical along an exposure pathway is essential to the determination of the potential for exposure. The science and methodology for evaluating the fate and transport of a chemical in the environment has continued to develop and has improved enormously over the past decade. Once exposure pathways are identified, the potential exposure can be quantified.

There are two possible exposure scenarios that must be considered. First, is there a potential for an exposure to a chemical? Second, if there is a potential for exposure then what is the acceptable concentration of that chemical at the point of exposure that will protect human health and the environment? Acceptable concentrations can be derived using chemical characteristics (including toxicity) or be based on concentrations such as the drinking water Maximum Contaminant Levels (MCLs) that have been published by regulatory agencies. If there is no potential for exposure, then there is no environmental risk. However, if there is a potential for exposure, then acceptable concentrations of the chemicals can be determined based on the risk management decisions and the physical and toxicological properties of the chemical.

One criticism of the risk assessment process that Mr. Montague presents is that the process of understanding exposure and toxicity ignores many "endpoints" and "sources". Mr. Montague is also critical of the process of scaling animal exposure data to human exposures. The process of risk assessment performed properly incorporates significant safety factors to account for relationships that cannot be quantified or effects that cannot be directly measured. Safety factors, incidentally, are used in all aspects of engineering from bridge building to aircraft design. Risk assessment advocates the use of sufficiently conservative assumptions to account for uncertainties in exposures and toxicity. In addition, the inclusion of the appropriate stakeholders in the definition of the concerns and the setting of risk management decisions by its nature allows for the stakeholders as a group to define the safety factors to their comfort level.

Once the risks and benefits of each of the alternatives have been quantified, the alternatives are evaluated. The evaluation should consider the:

• effectiveness of the alternative in protecting human health, safety and the environment;
• reliability of the alternative;
• short-term risk to the affected community, to those engaged in the implementation of the alternative and to the environment;
• acceptability of the alternative to the affected community;
• implementability and technical practicability of the alternative; and
• expected benefits of the alternative.

The goals of environmental risk-based decision making are sustainable development and improvement in environmental quality. Ultimately human health and the environment benefit greatly from the science of risk assessment and the application of risk assessment in risk-based decision making. Although risk assessment is a new science, it is rapidly maturing into an important and distinct discipline of its own. There is no question that the risk assessment process is not as well understood by scientists or the public as it should be. As with any new science, it will take time and better education in risk science for this to occur. It is reasonable to expect that there are many individuals such as Mr. Montague who do not understand risk assessment methods and especially who are not aware of the vast improvements and contributions of this science during recent years. There is no question that risk assessment will continue to evolve and mature and ultimately become a basic science of its own.

James R. Rocco, Manager, Environmental Remediation, BP Oil Company. Mr. Rocco has been with BP Oil for the past twenty-three years and has over twenty years of experience and involvement in the development, management and implementation of environmental compliance and corrective action programs related to the petroleum industry. He is currently responsible for environmental corrective action activities and related legislative and regulatory activities for BP Oil marketing, terminal, pipeline, and refinery facilities.

Lesley Hay Wilson, P.E., Senior Environmental Remediation Engineer, BP Oil Company. Ms. Hay Wilson has 10 years of experience in corrective action and currently provides consultation and senior review to BP corrective action project managers. In 1997, she was selected to receive a National Science Foundation Graduate Fellowship Award to investigate the use of Geographic Information Systems (GIS) in environmental risk assessment. She is currently completing the requirements for a Ph.D. in Civil Engineering at the University of Texas at Austin.

John E. Till, Ph.D., President, Risk Assessment Corporation. Dr. Till specializes in the development and application of models used for chemical and radionuclide risk assessment. He is the 1994 recipient of the Department of Energy's E.O. Lawrence Award for outstanding contributions to radiation dose reconstruction programs and effective leadership in public communication in the areas of radiological assessment, dose reconstruction, and risk analysis.