Health risk assessment Precautionary Principle

The antithesis of formulaic human health risk assessments for populations exposed to environmental contaminants, i.e., a post hoc process, is the precautionary principle, an ante hoc rationale. This approach appears to some as relatively draconian in its prescriptive formulation, i.e., no substances should be released into the human environment unless the likelihood of harm to health is determined to be acceptably small. 

Human health risk assessment of the type introduced above is not the only risk assessment modality operative in various areas. A second approach is that of the Precautionary Principle (see, for example, Percival 2006). The Precautionary Principle figures in health risk assessment to some extent but here it is presented for discussion within the final topic of this work, lead regulation. While this approach has been defined in various ways and often appears to be misunderstood, it basically describes a proactive, a priori, and more conservative methodology in terms of the consumer sector. This approach attempts to prevent or minimize risk of any public health and safety hazards before commercial introduction of a product occurs. Substances enter or do not enter the commercial domain based on evaluations generated beforehand. 

The use of human health risk assessment versus use of the Precautionary Principle through REACH depends, to some extent, on the nature of the risk and associated regulation and the stage of some economically useful substance s life cycle. The Precautionary Principle by definition is most relevant and applicable to ante hoc control over new substances prior to their marketing and entry into the environment or for assessment of new uses for existing substances already released into human environments. Sequenced and compartmentalized risk assessment methods extant in the United States by definition are post hoc tools for dealing with ongoing or potential risks from substances already in the human environment. 

The U.S. EPA and many other organizations point out that, when information about potential risks is incomplete, basing decisions to avoid unnecessary health risks is potentially the best option.8 When a good set of scientific data is available on a material, then the Precautionary Principle is not appropriate. Scientific data generated in the EU Risk Assessments or under risk assessment programs, such as REACH, that deem materials safe for continued use should effectively rule out the use of Precautionary Principle. 

Ashford, N. (2007) The Legacy of the Precautionary Principle in US Law The Rise of Cost-Benefit Analysis and Risk Assessment as Undermining Factors in Health, Safety and Environmental Protection. In de Sadeleer, N. (ed.) Implementing the precautionary principle. Approaches from the Nordic Countries, EU and USA. London Earthscan. 

The third and final aspect of the precautionary principle refers to the burden of proof for improving damage to health and the environment. It is typically regulators who are responsible for conducting risk assessments and ensuring a high level of health and environmental protection. The new EU chemicals policy seeks to reverse the burden of proof , requiring companies to do risk assessments and thereby demonstrate safe use for all chemicals (Section 2.4.1). 

Another view explores the limits of the risk assessment-based approach to decision-making and what a precautionary paradigm might look like. The precautionary principle 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, proponents of the precautionary approach see this as a means to make better, more health protective decisions in the face of highly uncertain and complex risks. 

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). 

Of particular note (1) These first guidelines called for revising each risk assessment as better information became available, a goal that has been rarely realized. (2) Gaps in scientific knowledge were to be filled with public health protective assumptions to err on the side of safety, an early application of the precautionary principle. 

The important role of risk assessment is to inform the public health decision process so that responsible decisions in the interest of public health can be made. Extreme application of the precautionary principle, whether motivated by public expectations or regulatory desire to achieve ever lower risk, can lead to a virtual zero tolerance policy it is the role of risk assessment founded on scientific principles to advise the reasonableness of these policy decisions. 

These two modalities also interact differently with public health policy. Conventional risk assessment helps inform efforts at secondary disease prevention or disease risk prevention by first quantifying the extent of contact with existing toxic substances and then the extent of harm to human and other populations from such toxic substances. The Precautionary Principle... 

The EU approach to chemicals control is based on a stepwise process of hazard assessment, risk assessment, and risk management. This process assists a rational prioritization in the allocation of limited resources to achieve a high level of health and environmental protection. Because this process often involves uncertainties due to insufficient or inconclusive scientific evidence, the precautionary principle may need to be applied in cases where there are indeed reasonable grounds for concern that health or the environment may be seriously endangered. The precautionary principle was first recognized in international law in the World Charter for Nature, adopted by the UN General Assembly in 1992. At the Rio Conference on the Environment and Development, Principle 15 states that in order to protect the environment, the precautionary approach shall be widely applied by... 

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