Joel Tickner

Lowell Center for Sustainable Production, University of Massachusetts - Lowell

While we have known for decades that many industrial chemicals are toxic, mounting evidence indicates that some of these chemicals play a role in the onset of diseases including cancer, developmental and behavioral disorders, respiratory ailments and asthma, neurological disorders, and birth defects, among others. Despite evidence of health effects linked to chemical exposure, a great majority of the chemicals found in our air, water, food, and everyday products lack basic safety data for human and ecosystem health, particularly that of developing organisms. Some of these chemicals are known to persist in the environment for decades, travel great distances, or accumulate in the food chain Even less is known about the potential health effects of exposures to multiple chemicals and other stressors: the reality of our everyday lives. While surveys have shown that the public believes that governments would not allow chemicals on the market if they had not been tested and demonstrated safe for use, this is clearly not the case.

The traditional scientific and political response to these data gaps has been to collect more information and use a technique called quantitative risk assessment to calculate the probability of harm given particular exposures, applying numerous assumptions in the process. While this process has been termed the "sound science" approach, it is often far from that. Quantitative risk assessments often narrow the types of information that go into decision-making and hide uncertainties. They are time-consuming and costly to complete and while debates over details of these assessments occur, the default policy option is that no policy action is necessary.

If we are to achieve more sustainable forms of production, we need a new paradigm for environmental science and policy that is based on the best available science (science informed), but also based on professional judgment, inclusion of a wide range of stakeholders, and consideration of the widest range of alternatives to meet particular needs. This approach, called the precautionary principle, is increasingly gaining prominence in international debates over uncertain risks. Put simply, precaution calls for preventive actions when there is reasonable scientific evidence of harm, although the nature and magnitude of that harm may not be fully understood scientifically. While a highly contentious term, we see precaution as simply an avenue to make more health protective decisions in the face of highly uncertain and complex risks.

In this section, we explore the limits of the risk assessment-based approach to decision-making and what a precautionary paradigm might look like. The Problem of Uncertainty. Our ability to identify adverse human health or environmental effects resulting from chemical substances is limited by our incomplete understanding of science, and therefore makes knowing what to look for and where to look extremely difficult. For example, the U.S. EPA and Environmental Defense Fund issued reports on the lack of basic testing information on toxic substances in 1997 and 1998 (EDF, 1997; U.S. EPA, 1998a). They found that of the 2800 high production volume (HPV) chemicals (over one million pounds in commerce), 93 percent of chemicals included lack some basic chemical screening data, 43 percent have no basic toxicity data, and 51 percent of chemicals on the Toxic Release Inventory lack basic toxicity information. While these reports resulted in the EPA's High Production Volume Challenge (a voluntary effort of the U.S. EPA, the American Chemistry Council and Environmental Defense), which seeks to fill out these gaps, only basic toxicity information for a small number of chemicals will be addressed (for example, data on chemicals used from 10,000 lbs to one million lbs will not be included). The Challenge will not include exposure information or address how data should be used in risk management and reduction. As of fall 2003, one-fifth of the HPV chemicals lacked a commitment from industry for testing (see

Our scientific knowledge is especially limited on the effects of pollution on highly variable and complex ecological and human systems. A question for decision-makers is how science can establish an assimilative capacity - a predicable level of harm from which an ecosystem can recover - or a "safe" level of exposure when the exact effect, its magnitude, distribution, and interconnections are unknown (Gee, 1997).

Traditionally, decision-makers have focused on the effects of a single chemical in a single medium, when in reality humans and ecosystems are exposed to a wide variety of physical and chemical stressors, circumstances that environmental science is still struggling to understand. Further, specific populations feel disproportionate impacts of environmental degradation; certain groups may be at higher risk of harm because of genetic disposition, disease, developmental, or social status, and geographic location. For example, children are uniquely susceptible to the effects of toxic substances due to their immature metabolic processes, rapid development, and exposure (Landrigan, 1999). That sensitive subpopulations or high variability in responses to chemical exposures exist within a group are frequently overlooked by decision-makers. Uncertainty is an inevitable condition underscoring all environmental decision-making because humans operate in open, dynamic environments that are difficult to control. For example, variability among individuals generally cannot be reduced. In addition to traditional types of uncertainty, there are also the conditions of indeterminacy (an uncontrollable form of uncertainty due to complex human, technical, and social interactions) and ignorance (the state of not knowing what we do not know; e.g., not knowing what we are uncertain about) (see Wynne, 1993).

Unfortunately, the lack of proof of harm is often misinterpreted as proof of safety. And, because uncertainty complicates decision-making, it is generally played down or ignored. The influence of uncertainty and ignorance, for example, is seen in policy when EPA permits the use and release of chemicals into the environment without having toxicity information. Despite this lack of knowledge, the Toxic Substances Control Act presumes that existing chemicals (those sold before 1980, accounting for more than 99 percent by volume of chemicals on the market today) are safe until proven dangerous. This presumption is not only problematic for health but also a serious limitation to innovation in safer chemistry.

Because uncertainty is underappreciated, early warnings of harm are often overlooked. A review of technology failures saw in 40 percent of the cases, some early sign of harm was overlooked. In 50 percent of the cases, danger signs were known for a similar technology (Lawless, 1977). Many substances once thought benign have been shown to cause severe human or environmental effects. Case studies and common-sense observation often suggest causal links long before they can be proven. For example, concerns about the health hazards of asbestos and benzene were identified as early as 1898 (European Environment Agency, 2000). Lead has been known for centuries to be a neurotoxicant. These cases show how waiting for "convincing" evidence can pose high costs to human and ecological health, and remediation resources. The Problems of Risk Assessment. Over the past 25 years, the United States regulatory and scientific response to environmental damage and uncertainty has focused on the use of quantitative assessment methods. This response was heavily influenced by the U.S. regulatory and political system, as well as the courts, where threats of judicial scrutiny have caused agencies to constantly construct formal, quantitative records (von Moltke, 2000). During the 1970s, risk assessment and cost-benefit analysis were developed to assist decision-making regarding environmental and health risks.

Defined by the National Research Council in 1983, quantitative risk assessment has become a central element of environmental and health decision-making in the United States. Risk assessment is not a scientific discipline, per se. It is a formalized, systematic tool used to integrate and communicate scientific information. The technique of risk assessment has evolved over the years to address different disease endpoints and to incorporate broader notions of exposure and greater analysis of uncertainty. But the general framework for conducting risk assessments remains the same: hazard identification, dose-response assessment, exposure assessment, and risk characterization (National Research Council, 1983). The development of risk assessment has brought substantial advances in scientific understanding of exposure and disease and our ability to predict adverse outcomes from hazardous activities. When much is known about the specific nature of the harm and probabilities are well established, risk assessments provide a science-structured methodology for decision-making. Nearly all decisions involve some weighing of risks, either qualitatively or quantitatively.

The reliance on risk assessment as the sole analytical technique in environmental and health decision-making has significant and widely described disadvantages (see Tickner, 1996; O'Brien, 2000), yet reliance on this technique is increasing. Specific criticisms of the use of quantitative risk assessment as a central, singular tool in regulatory decision-making include the following:

• Risk assessments are generally used to analyze problems rather than to solve or prevent them, and are used to set "safe" levels of exposure that correspond to a predetermined "acceptable" level of risk.

• Risk assessment limits the amount and source of information used in examining environmental and health hazards that may inhibit holistic understanding of complex systems and interactions.

• Risk assessment perpetuates many of the inherent limitations in current scientific methods. For example, research questions may be so narrowly defined that important aspects of the problem are missed.

• Risk assessments limit consideration of uncertainties, multiple exposures, cumulative effects, sensitive populations, or endpoints other than cancer.

• Risk assessments are based on numerous assumptions that are many times based on political or uncertain information. As a result, risk assessments conducted by different groups, even using the same information, can come out with widely differing results.

• Risk assessments can be expensive and time consuming, tying up limited resources. It may be much more cost-effective to prevent exposure in the first place. An example of this is the U.S. Occupational Safety and Health Administration's Methylene Chloride standard, which took seven years to finalize due to debates over a pharmokinetic model and mechanism of action.

• Risk assessment processes often exclude those potentially harmed by environmental degradation as they traditionally do not include public perceptions, priorities, or needs.

Risk assessment poses additional problems when it forms the basis for decision-making because it creates a rigid structure in which narrowly defined evidence of harm is collected, the probability of adverse effects is examined, and a decision is made. Additionally, feedback and follow-up are not guaranteed, alternatives or prevention are not generally considered, and the public is only told about risk once a decision is imminent.

Government agencies have begun to recognize and respond to criticisms about risk assessment and its use, and have noted areas for improvement. Reports by the National Research Council (1994; Stern and Fineberg, 1996) and the Presidential Commission on Risk Assessment and Risk Management (1997) recommended changes to the process of risk assessment that would:

• Better and more comprehensively examine uncertainty and variability;

• Include stakeholders throughout the assessment and management process;

• Consider prevention and options in the risk assessment process;

• Provide more holistic problem definition;

• Consider cumulative/interactive effects and sensitive subpopulations; and

• Better evaluate actions taken.

While these recommendations point to needed change, momentum for their implementation is missing. A trend towards more "reductionist" risk assessments (where action is not taken until the mechanism of action of effects is fully understood) does not bode well for such positive changes. Further, some analysts suggest that all risk decisions fully consider and quantify "risk-risk" trade-offs of regulations - for example, natural versus chemical carcinogens, or the beneficial aspects of pollution (Graham and Wiener, 1995). While it is important to consider potential trade-off risks from decisions and account for them through flexible decision-making structures, such a requirement would create additional burdens that may stall preventive public policies. Precaution: Response to the Limitations of Current Quantitative Assessment Frameworks, Uncertainty, and Complexity. Because risks associated with toxic substances are increasingly complex, and widely distributed, there is a need for a new approach that uses the best available science and informed judgment to protect health and ecosystems and stimulate innovation in safer and cleaner materials. Embodied in the precautionary principle, this approach is rapidly gaining strength in environmental health debates because it encourages policies that protect human health and the environment in the face of uncertain risks. In this broad sense, precaution is not a new concept and is at the heart of centuries of medical and public health theory and practice. The principle originated in response to concerns that science and policy structures were inherently too limited to adequately address evolving risks, and recognized the severe consequences to health and the economy of not taking preventative actions.

As a principle of decision-making, the precautionary principle has its roots in the German word Vorsorgeprinzip. An alternative translation of this word is the "foresight principle" or "forecaring principle," which emphasizes anticipatory action - a proactive idea rather than precaution, which to many sounds reactive and even negative. The Germans saw precaution as a tool to stimulate careful social planning for job creation, innovation, and sustainability. Over the past 20 years the principle has served as a central element in international treaties addressing North Sea pollution, ozone-depleting chemicals, fisheries, climate change, persistent organic pollutants, genetic modification, and sustainable development. The European Union has placed precaution, pollution prevention and the polluter pays principle, as central elements of environmental health policy. While not explicitly mentioned, the precautionary principle is at the core of many environmental and occupational health policies in the United States (Raffensperger and Tickner, 1999).

All definitions of the precautionary principle are similar, essentially stating that when there is uncertainty and credible evidence of a risk, then precautionary actions should be taken. The most widely used definition of the precautionary principle is the 1992 Rio Declaration on Environment and Development, which states

In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.

Another widely used definition is the Wingspread Statement on the Precautionary Principle, which states "when an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically." The statement elaborated on earlier definitions by identifying four central components of the Principle: (1) taking preventive action in the face of uncertainty; (2) shifting burdens onto proponents of potentially harmful activities; (3) exploring a wide range of alternatives to possibly harmful actions; and (4) increasing public participation in decision-making (Raffensperger and Tickner, 1999). Components of a Precautionary Approach. Implementing the precautionary principle to protect health and ecosystems from chemical risks demands broad reorganization of environmental science and policy to increase their efficacy in anticipating risks and promoting cost-effective alternatives to risky endeavors. Elements of effective use of the precautionary principle in policy include the following (Tickner, 2002).

1. Shifting the questions asked in environmental and health policy. Instead of scientists and policy-makers asking, "What level of risk is acceptable?" or "How much contamination can a human or ecosystem assimilate?" we must ask, "How much contamination can we avoid while still achieving our goals?" "What are the alternatives or opportunities for prevention?" "Is this activity needed in the first place?" This requires tools to analyze comprehensively not only risks but also feasibility of alternative technologies and products.

This shift reorients regulatory focus from analysis of problems to analysis of solutions and establishment of goals. Goal setting, common in public health, involves backcasting, or establishing long-term goals and shorter term objectives to reduce impacts and exposures of problem substances, and advocates for alternatives. This focus on alternatives and goals allows a product or activity as a whole to be examined as to whether its purpose can be served in a less harmful or more effective way, and may also allow decision-makers to make better use of resources by avoiding costly debates over proof of harm and causality.

2. Shifting presumptions. The precautionary principle favors protecting the environment and public health in the face of uncertain risks, rather than presuming that a substance or economic activities are safe until proven dangerous. This places the responsibility for demonstrating relative safety, analyzing alternatives, and preventing harm on those undertaking potentially harmful activities and allows for legislative disincentives for potentially harmful activities.

3. Transparent and inclusive decision-making processes. Environmental health decisions tend to be primarily policy decisions, informed by science and values. A more participative process for decision-making under the precautionary principle could improve the ability of decision-makers to anticipate and prevent harm to ecosystems and human health. Public participation is vital to development of accountable solutions to environmental health problems because nonexperts see problems, issues, and solutions that experts miss, reflect sensitivity to social and political values and common sense not included in expert models. Broader public participation processes may increase the quality, legitimacy and accountability of complex decisions. Precautionary Actions. There is a misconception that the precautionary principle requires banning an activity. Precautionary actions range from public right-to-know, to phasing out particularly harmful activities. The appropriate precautionary action should come after considering the strength of the evidence, magnitude and potential impact of the risk, uncertainties, opportunities for prevention, and social/economic values. The goal of such actions should be:

• Reducing and eliminating exposures to potentially harmful agents, minimizing trade-offs;

• Redesigning production processes, products, and human activities to minimize risk in the first place;

• Providing information and education to promote empowerment and accountability;

• Establishing a research agenda designed to characterize more comprehensively risks, provide early warnings, and develop alternatives.

Many possible tools for the precautionary approach are outlined in this book, including cleaner production, environmental management systems, and so on. Precaution and Environmental Science. When the precautionary principle is discussed in its relationship to science, it is often portrayed as an antiscience or a risk-management principle that is only used after undergoing conventional scientific processes. As discussed earlier, in practice the limitations of science to characterize complex risks show that precaution is not at odds (Kriebel et al., 2001). Further, precaution is not just about additional safety factors or changing risk assessment default assumptions. Research by U.S. EPA scientists has demonstrated that many of the EPA's Reference Doses - or conservative safe exposures - may correspond to risks of greater than 1 in 1000, meaning that safety factors alone may not protect health (Castorina and Woodruff, 2003).

Environmental science is critical to solving some of our most pressing and complex environmental problems and hence can support precautionary policies. As environmental science faces increasing challenges from more complex risks with greater uncertainty and ignorance, the nexus between science and preventive policy is even more important. In this context, precaution is entirely consistent with good science because it demands more rigorous and transparent science rather than less science. This provides insights into how systems are disrupted by technologies, identifies and assesses opportunities for prevention and restoration, and clarifies gaps in our understanding of risks. A shift to more precautionary policies allows scientists to think differently about the way they research and communicate results (Kriebel et al., 2001). In September 2001, the Lowell Center for Sustainable Production hosted the International Summit on Science and the Precautionary Principle to explore the role of science in the precautionary principle and advocated the following changes to science and policy (Tickner, 2003):

• A more dynamic interface and communication between science and policy;

• A more effective linkage between research on hazards and expanded research on prevention, safer technological options, and restoration;

• Greater use of interdisciplinary approaches to science and policy, including better integration of qualitative and quantitative data;

• Innovative methods for analyzing the cumulative and interactive effects of various hazards, for examining impacts on populations and systems, and the impacts of hazards on vulnerable and disproportionately affected communities;

• Systems for continuous monitoring and surveillance to avoid unintended consequences of actions, and to identify early warnings of risks; and

• Better analysis and communication of potential hazards and uncertainties.

A more precautionary approach should be informed by the most "appropriate science", which can be understood as a framework for choosing methods and tools chosen to fit the nature and complexity of the problem (Kriebel et al., 2003). Critical to this framework are the flexibility to integrate a variety of research methods and data sources into the problem evaluation, and to consult with many constituencies to understand the diversity of views on a problem and seek input on alternative solutions. Appropriate science is solutions-based, focused on broadly understanding risks, but also on finding ways to prevent them in the first place. Under this approach, the limitations of science to fully characterize complex risks are openly acknowledged, making it more difficult to use incomplete knowledge to justify preventive actions. Precautionary Assessment: More Sustainable, Preventive Decisions Under Uncertainty. Applying precaution to achieve more health and ecosystem-protective decisions under uncertainty requires a set of cautionary considerations that are applied throughout the scientific and policy process, such as analysis of alternative courses of action, expanded scientific tools, incentives for research and innovation, and enhanced public participation. It should encourage decision-making using the broadest possible range of information, stakeholders and scientific and policy tools in identifying and preventing risks. These can ensure a more proactive and positive approach to environmental protection, while improving decision-making and stimulating innovation in safer materials, technologies, scientific approaches, and policies.

One approach to this process is called "precautionary assessment," which focuses on a series of procedural steps to ensure sound health and environmental decision-making, examining all of the evidence on threats as a whole and learning from accumulated experience and understanding (Tickner, 2003). It is a flexible approach, which is critically important in environmental decision-making since each decision is different. Although outcomes will differ with the facts of each case, the approach will be the same. The goal is for governments and entities handling risks to internalize this heuristic approach in their decision-making processes, instituting a precautionary "mindset" with regard to uncertain environmental and health risks. Similar approaches exist and are increasingly used in analyses of complex issues, such as medicine and business decisions.

The steps of a precautionary assessment approach include the following.

1. Determining whether an uncertain risk/problem merits a more thorough review - sometimes a screening process may be useful.

2. Broadly defining problems to capture root sources of risks.

3. Considering and examining all available evidence on exposure, hazard, and risk in an interdisciplinary manner, to take account of variability as well as direct and indirect, cumulative, and interactive effects.

4. Considering simplifying rules of thumb, safety factors, default values, or proxy indicators of exposures and effects when information is lacking.

5. Comprehensively examining and reducing uncertainties and gaps in knowledge.

6. Identifying and examining a wide range of options to reduce risks, as well as their trade-offs, advantages, and disadvantages.

7. Determining an appropriate course of action based on the scientific evidence, examination of alternatives, and public input.

8. Instituting post-implementation follow-up measures to ensure continuous risk reduction and minimize unintended consequences.

Decisions made under a precautionary assessment should not be considered permanent, but part of a continuous process of increasing understanding and reducing overall impacts. Once precautionary actions have been chosen, follow-up and monitoring schemes for the activity should be developed. This type of feedback is critical to understanding the impacts of precautionary actions as well as to stimulate continuous improvement in environmental performance and technological innovation. Follow-up tools include periodic assessment, audit, or prevention planning requirements; regular reporting of environmental impacts (e.g., toxics use reporting); short-and long-term health and exposure monitoring; toxicological testing; and impact statements any time a major change is made to a product, process, or activity. Conclusions. This section has outlined the problem of uncertainty in preventing risks from chemical exposures and the limitations of current scientific and decision tools based on the concept of risk assessment. It has outlined a new paradigm for decision-making for sustainability embodied in the precautionary principle. This approach has several key aspects:

• Expanding scientific tools to define more holistically and characterize risks in an interdisciplinary manner.

• Going beyond border of diagnosis to solutions - focusing on more comprehensive characterization of risks and uncertainties but placing equal emphasis on developing and studying alternatives that can reduce risks.

• Incorporating a diverse range of tools, options, stakeholders, and an ability to build on knowledge - the whole of the evidence - in making the most robust decisions under uncertainty.

• Redirecting research funding to greatly increase budgets for research and development of safer chemicals, processes, and products, and more holistic analyses of risks. For example, the U.S. EPA's budget for development of safer chemistry - green chemistry - amounts to about four million dollars, about the same as the cost of a laboratory cancer study for a single chemical!

The process of precautionary assessment outlined above is not meant to provide rigid rules for invoking the principle, but rather a structure for stimulating consistent and thoughtful application of precautionary thinking. Such a process - one that examines the whole of the evidence from various sources, examines a full range of alternatives, and injects sensible judgment and values - can produce more sound and sustainable decisions. In this sense, precaution is about how do we make more health protective decisions under uncertainty and complexity and how do we achieve the products, services, and technologies we want while minimizing their potential impacts. The ability to adapt current policies and approaches to decision-making that do not readily support precaution will require technical capacity to examine risks and solutions in new ways and capable institutions that comprehensively and fairly apply precautionary procedures. It will also require new mandates and guidelines so that a more precautionary framework and procedures are broadly applied throughout environmental decision-making processes. And, ultimately, it will require important institutional changes in government and industry, and changes in the conduct of environmental science.

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