Introductory remarks to session on risk assessment and risk management
Post on 01-Jan-2017
FUNDAMENTAL AND APPLIED TOXICOLOGY 4, S380-S382 (1984)
Introductory Remarks to Session on Risk Assessment and Risk Management
Bureau of Foods, Food and Drug Administration, Washington, D.C. 20204
As you see from the program, in essence, this phase of the discussion really has two parts, one dealing with the issues of risk estimation, the statistical quantification or attempts at quantification of risk, and the other is asso- ciated with what one does about the process, the management part of risk.
What I would like to do in introducing our discussion today is to say a word or two about the way in which the concept of a process of risk assessment impacts on the law, or to say it differently, how the U.S. food law encom- passes the possibility of this kind of process and what impact a great use of this process might have in this regard.
The interface between science and law oc- curs almost entirely in the realm of this process we call risk assessment. At times the debate on these issues and its values and its process takes on the trappings of a Medieval discussion on metaphysics. A large part of the problem as to why this occurs has been due to the lack of recognition that risk assessment is not sim- ply an advanced statistical technique, but rather it is a process, one that is complex, not well understood, and in each of its steps still pretty much of an art.
For the purposes of our discussion today, let us view risk assessment as consisting of three stages. First is hazard identification; sec- ond, risk estimation; and third, risk evaluation. The first, hazard identification, we have spent the last two days in discussing, at times with what appear to be contradictory results and
at other times with, I think, clear direction as to where we are going.
The second, risk estimation, is the subject of todays discussion, and the third, risk eval- uation, which would include the problem of management of risk, we will discuss tomorrow.
Before we begin our discussion this after- noon, it may be of interest to briefly look at the U.S. law within its conceptual frame- work.
U.S. food law is a complex of often arcane components modified throughout the years by a variety of amendments, each of which represents the science of the time and each of which is, also, representative of social mores of the times. There are various sections, some of which appear to be contradictory, but each section applies to a different component of the food supply and within each section the differences are, in fact, representative of im- plicit generic risk/benefit decisions that were made by the Congress at the various times at which the amendments were made.
Section 402, for example, which deals pri- marily with foods perhaps more than food additives, is little concerned with focusing re- sources upon identification and estimation of hazards. Instead it is concerned primarily with the evaluation or the management phase of risk assessment. More than anything else, this section of the law represents a societal response to a known hazard in the food supply, and that is not surprising when you realize it is one of the older sections of the law dealing
0272-0590/84 $3.00 Copyright 8 1984 by the Society of Toxicology. All ri&ts of reproduction in any form reserved.
INTRODUCTORY REMARKS S381
with issues which were recognized as far back as 1938.
Of course, this response is very risk aversive for it aims to reduce the probability of harm by protecting even the most susceptible seg- ments of the population.
The ordinarily injurious standard of this section applied primarily to foods, also, makes a strong statement about evaluation because it tolerates a higher risk than the may render standard which is applied to things like food additives. It indicates some societal judgment that foods in their traditional sense are more valuable than added substances. Dick Merrill has observed that apparently the original in- jurious standard was meant to permit the FDA or a District Court for that matter to weight the relative dangers and importance of foods that naturally contain poisonous constituents. In contrast to Section 402, Section 409 which is a more recent section opened the way for a much greater emphasis on the first two stages of risk assessment; by requiring premarket safety reviews and permitting the establish- ment of tolerances, it demanded that some consideration be given to the nature and extent of hazards posed by substances at various lev- els of exposure. This revision is still, however, risk aversive in its approach to the evaluation phase. It does not explicitly permit consid- eration of a substances benefits in determining what might be an acceptable level of exposure. Instead, it assumes that a threshold dose can be established below which most of the pop- ulation will not experience any injury.
Of course, the risk of aversive response is carried to its extreme in the Delaney amend- ment of this section where no amount of a carcinogenic additive is permitted.
Now, the consequences resulting from stat- utory structures regarding risk and risk as- sessment have been numerous and far reach- ing. One such example is the expression of generic risk/benefit judgments by the legis- lative through its different attitudes towards risk among various legal categories of sub-
stances, and I have already mentioned that. Undoubtedly, however, the most important consequence of our present legal structure arises from the shift of the burden of proof from the government to the sponsor of the substance.
In the early days of the Food, Drug, and Cosmetic Act, requiring the government to show that a substance was unsafe tended to focus attention on acute hazards where evi- dence was available and essentially indisput- able. On the other hand, requiring that a sponsor demonstrate safety opened the way for full inquiry into the spectrum of possible hazards, chronic as well as acute, that might be posed by a substance.
The unleashing of this authority in 1958, at a time when tremendous advances were being made in the biological sciences and an- alytical chemistry, led to a growing interest in hazard identification. This important conse- quence has in turn impinged strongly upon the regulatory system in various ways.
For example, our universe of safety con- cerns has expanded with respect to both the sources of hazard and the types of hazard.
Today chemicals routinely can be identified and quantified at levels around 1 ppb.
We must now ponder the effects of chronic low level exposures to numerous substances. In addition, our concerns have grown about environmental contaminants such as aflatox- ins, and there is increasing evidence that many natural components of foods can be toxic.
Our spectrum of health interests has broad- ened, as we have seen in the last two days, to include phenomena such as mutagenesis, car- cinogenesis, and behavioral effects, and to complicate matters more problems exempli- fying individual variability, food allergies, hy- perkinesis, hypertension, lipemias, and so on, just to name a few of them, have gained at- tention.
Ironically, as our sophistication about the types of hazards has increased, we have be- come enmeshed in what has been called the
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information paradox. For each quantum of uncertainty we have attempted to reduce in the identification state of risk assessment, we have multiplied our uncertainty in the esti- mation phase because we often lack indicators of the true extent of possible hazard.
One type of response to this situation has been predictable. Interest and controversy have mounted over the most appropriate ways to estimate human risk.
It is the purpose of this part of our sym- posium to address some of the issues asso- ciated with this part of risk assessment. The
previous discussions concentrated on the identification of hazards and the approaches required to increase the certitude of their ex- istence.
At this point we will turn to the issues of risk assessment and risk management. This afternoon we will attempt to define the various ways in which risk has been quantified and/ or attempted to be quantified. In addition, we will attempt to identify the problems asso- ciated with this activity as well and to indicate the points of uncertainty in making the esti- mations.