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Proceedings of the 4th National Symposium on Biosafety
Risk Assessment
Michael McElvaine, DVM, PhD
USDA
1325 13 Street NW, No. 32
Washington, DC 20005My experience in risk assessment has been with the risk of animal disease associated with animal imports. However, the philosophy of risk assessment can be applied to almost any situation you can think of, including the laboratory.
Risks, what are risks? Risks are part of every thing we do; we consider the risk before we make almost every decision in our lives. Before making a decision, you're looking at what bad outcomes can happen, what good outcomes can happen and what is the likelihood of each possibility. Risk assessment itself is not new. You can think back to the prehistoric times when the cave man would have to compare the risk of going out and hunting for food and maybe getting eaten by a saber tooth tiger against the risk of starvation. Certainly, we are not cave people but you do the same thing when you get up in the morning and take your car into work. You have to consider the risk of having an automobile accident as compared to the risk of staying home and losing your job and your pay check. We all consider risks as we make decisions.
Formal risk assessment methods were first used in engineering and economics. In the last couple of decades, these methods have been applied to health risk studies and questions of biologic risk. Even more recently, there has been an emphasis on using cost-benefit analysis based on risk assessment.
Before we proceed any further, I would like to talk a little bit about language. As we've heard in some of the presentations over the last few days, there are differences in language, differences in definitions. In the field of risk assessment you will note very great differences in how words and concepts are defined, depending on whether you're talking to the National Research Council, talking to the EPA, or to an engineer. What I want to warn you about here is that in every situation, whomever you're listening to, whatever you're reading, you should try to make sure that you are using the same vocabulary. Don't assume that you know what they mean when they use a word because they may be meaning something completely different. And, don't assume that because they're using a word you're not familiar with that maybe they're really using an alternate word for something with which you are familiar. So make sure you are using a common language and vocabulary. This will improve your communication greatly.
In order to improve our communication today, here are a few definitions my group has used in our work with risk assessment. I think these definitions can be further applied to your own particular situations.
Risk assessment is the whole process for identifying a hazard and evaluating the risk of the specific hazard either in absolute or relative terms. This may be in terms of either a qualitative assessment or a quantitative assessment. Risk assessment also includes estimates of uncertainty. Uncertainty is a very big subject that you have deal with when you're doing risk assessment; I'll be taling more about that later. A risk assessment is an objective, repeatable, scientific process.
When we talk about a hazard we talk about the act or phenomenon which has a potential to produce harm or any other undesirable consequences. In the biologic or laboratory situation, you may be considering such hazards as infections, zoonotic diseases, injuries, economic outcomes, etc.
We have already heard several people talk about risk management today. The definition I use is that it is a pragmatic, decision making process concerned with managing risks. Risk management encompasses all the different things that relate to the decision, not just what may happen in the laboratory. When you are faced with the risk of the transfer of a zoonotic disease or of an accident in the laboratory you are dealing with many other things. You're dealing with policy; you're dealing with regulations; you're dealing with society; you may even be dealing with politics. The risk manager must consider a broad range of factors.
We define risk communication as an open, two way exchange of information and opinion about risk leading to better understanding and better risk management decisions. That's a very lofty statement and is a daunting task. Several people today have already talked about this. I think risk communication may be the biggest challenge in the overall picture in managing risk in our workplace and our world.
The last definition for today is risk analysis. This is an umbrella term that includes the entire process of risk assessment, risk management and risk communication. We've heard other people use the term risk characterization this afternoon, too. There is currently a lot of debate about the definition of risk characterization. Many people use that term interchangeably with risk analysis. But the basic idea is that risk analysis encompasses everything else that goes underneath: the risk assessment, the risk management process and the risk communication process.
What is risk assessment? In short, you can define risk assessment by these three questions: What can go wrong? How likely is it? And what will the consequences be? This afternoon we've heard people talk about dose-response relationship. This comes from the EPA health risk assessment paradigm. In a biologic situation where we're dealing with infectious organisms, organisms that may multiply, dose-response is a little bit harder to quantify than if you're just dealing with a chemical agent that does not proliferate. We often find it more useful to use a failure event analysis where we consider the probability of the event occurring before considering the dose-response model.
This model gives an overview of the risk analysis process that I just described. It shows that risk assessment and risk management are two separate processes. However, there needs to be interaction and communication between the two processes in order to have a successful outcome. Risk assessment provides the tools and options to the decision makers. It is the responsibility of the risk manager to evaluate the outcomes and make the decision. Risk communication is represented by a separate box with arrows that extends through the whole process. In order to have a good outcome, risk communication should be part of the entire process from start to finish. You may not succeed if you wait until after a decision is made before you consider how you will communicate the decision to affected parties.
There are a variety o different methods for doing risk assessment. I have already mentioned that there is more than one type of model that can be used. In addition, there are a variety of methods that can be used to evaluate the risks. Among these methods are qualitative, semiquantitative, quantitative and combination methods. For the qualitative method, you are basically using language and words you to describe how big the risk is and what is the probability of this risk. For the semi-quantitative methods, you are applying numbers and scales onto the qualitative risk assessment which will help you better prioritize your risks. For a quantitative risk assessment, you are using the best numerical values available to estimate the risks. This gives you great flexibility in prioritizing and measuring risks and also measuring the amount of risk reduction that may be attributable to each risk mitigation method. Combination methods may include all of the above methods. There is no single, best method for risk assessment. It is important that you select the method that will provide you the best answer to your particular situation.
Next, I would like to describe the characteristics of a good risk assessment. First, a good risk assessment should be scientifically based. By that, I mean that you should use the best science, the best information available. Second, it should be consistent in that you use methodologies that are accepted by the general scientific community. Third, a good risk assessment should be well documented. I'm sure that many of the agencies that you work for require documentation for everything you. What I mean here, is that you need to document your decision process and the information you based your decision on. This is especially important when you are dealing with situations of multiple risks where there may need to be consideration of tradeoffs when you describe risk mitigation options. Fourth, a good risk assessment should be flexible. In many situations you'll find that there are many methods that are useful. As I mentioned before, you need to use the method that will provide you with the most useful information for the decision maker. You may need to use very different methods for assessment of injury risks than you would for the risks associated with zoonotic diseases. You need to be flexible in your methods. The last characteristic is transparency. By that I mean that you provide all the information in a clear and orderly manner such that another assessor could review the assessment, understand the rationale and come up with similar conclusions.
A good risk assessment will provide you with several useful outcomes. A good risk assessment will help you rank your risks and develop priorities for the management of these risks. You will be able to identify where you should invest your resources of time and money. You may not be able to actively deal with all risks all the time. The brutal truth is that you never achieve the so-called "zero risk". As scientists, you already appreciate that zero may never exist and that the concept of 100% may not exist either (except, of course, for such things as death and taxes). A good risk assessment also helps you compare risks. This is especially helpful when you are considering situations with many possible risks and many different types of risk. A good risk assessment will help you identify points for risk reduction. As you examine the whole risk pathway and the probabilities associated with each pathway, you will be able to identify the places where there can be effective risk reduction. Similarly, a good risk assessment helps you to identify areas where you need more information and what is the most important information that we need to make a decision. Lastly, a good risk assessment will help you with risk communication by identifying the factors that are important for communication with your different audiences in order to get a better understanding of the risks involved and the management options.
In closing, I would like to share with you one of my favorite quotes about risk assessment. It is also a quote with which I strongly agree. This has been called the First Pinciple of Risk Assessment, "Before you can MANAGE something, you must first be able to MEASURE it." As a risk assessor, you have to be able to measure the risks and provide that information to the manager. If you cannot measure something, how will you even know if you are actually managing anything?
During the breakout session, we will be able to discuss the concepts of uncertainty and variability, important concepts that I was not able to discuss at this time. I will also be glad to address any specific questions that you may have. And with that I thank you.
Risk Assessment
Breakout SessionRapporteur: Mr. Ronald E. Larson
irector, Toxicology Operations
Corning Hazleton Inc.
PO Box 7545
3301 Kinsman Blvd
Madison, WI 53707
608-241-7224We had a small but spirited group that was intensely interested in the issue of risk assessment. We started out by defining the issue of risk assessment in saying that the Occupational Health Program is in and of itself a risk assessment program. There is a history to risk assessment, and in our lifetimes it's first been commonly seen as an engineering process. We're probably all familiar with risk as done by the Environmental Protection Agency as it has to do with waste sites and pesticide evaluations, and Dr. Michael McElvain, who was the leader of our discussion and the presenter yesterday, is working on risk assessment with the USDA in disease risk in animals. One of our group offered that they had recently been involved in classification of infectious agents as a matter of risk.
The application of the science of risk assessment is fairly new. There are a couple of master's degree programs that people were aware of around the country that now offer a degree in risk assessment. The science can be applied to just about anything that you want to apply it to. If you looked at the program from the last couple of days, certainly it can be applied to chemical, physical, and zoonotic risk as well as assessing the risk of giving various people access to your facilities and the risk associated with personal protective devices.
There is a principle that we identified as being associated with the notion of risk management, If you believe in risk management principles then you first must be able to measure it before you can manage it. Therefore, we will allow a maximum risk to be X and you can pick for yourself what you want that maximum risk to be. The notion here is that you can quantitate it to some degree and make a better decision based on that quantitation.
There is a methodology to risk assessment. Risk assessment needs to rely on databases. Michael shared with us something called a probability density function that shows that the likelihood that each point under a data curve is likely to be true. If you have that sort of mathematical formula it increases your level of certainty in decision making.
There was also recogniton that it definitely is not an exact science. Someone commented that the area in the middle of the curve is definitely muddy when it comes to decision making.
We also talked philosophically a bit about our willingness to live without this tool. We spend a lot of money on personal protective devices without ever really quantitating risk. We spend money on facility design without understanding fully the issues of risk. Many of us spend money nearly ever week or perhaps even twice a week on lotteries when our odds are 1 in 53 million of winning. We never think really about the 1 in 53 million odds. We'd rather think that lady luck is going to give us a turn. This gets into a kind of emotional/political decision making having to do with risk assessment. Many of us would rather rely on our intuition. We have a great deal of faith in our intuition rather then quantitative numbers.
In times of tighter dollars the analysis associated with a formal risk assessment process may become more and more cost effective. At the risk of overstating the obvious the proof is that the Biosafety meeting program could have easily been written in a slightly different fashion considering how many times the words "risk assessment" were used. You could have attached those words in front of nearly everything we've discussed here in the last few days. Risk assessment of zoonoses, risk assessment of face protection, risk assessment of sharps management, and so on and so forth. In summary this may be just the beginning of something that we all will value much more in the future.
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Last Modified: 1/2/97
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