The committee agrees with many of those concepts discussed and recommended in Improving Risk Communication (NRC, 1989). Many of those concepts have been incorporated into EPA guidance documents on risk communication (see, for example, Covello and Allen, 1988; EPA, 2004, 2007). In 2007, for example, EPA’s Office of Research and Development published Risk Communication in Action (EPA, 2007), which describes the basic concepts of successful risk communication, taking into account differences in values and risk perception, and includes instructions on how best to engage with and present risk information to the public. It is not clear, however, the extent to which that and other documents—which are not agency-wide policies—are considered by or implemented in the risk communication practices of different programs and offices at EPA. Other National Research Council (NRC) reports (1996, 2008) have expressed concern that stakeholders have not been adequately involved in EPA decision making, suggesting that two-way risk communication, including communication surrounding uncertainty, may in some instances be inadequate.

The extent to which uncertainty is described and discussed varies among EPA’s decision documents. Chapter 2 discusses EPA’s decisions and supporting documentation around arsenic in drinking water, the Clean Air Interstate Rule (CAIR), and methylmercury, including the uncertainty analyses that EPA conducted and presented for those regulatory decisions. Those examples indicate that EPA does sometimes conduct numerous uncertainty analyses and present those analyses in its documents. Such analyses, however, are often presented in appendixes, and the ranges of potential outcomes are not necessarily presented in the summaries and summary tables. The committee also noted that the uncertainty analyses in those documents focus almost exclusively on the uncertainty in estimates related to human health risks and benefits. Krupnick et al. (2006) reviewed four of EPA’s regulatory impact analyses for air pollution regulations, including CAIR and the Clean Air Mercury Rule. They concluded that although the documents “indicate increased use of uncertainty analysis,” the EPA’s regulatory impact analyses “do not adequately represent uncertainties around ‘best estimates,’ do not incorporate uncertainties into primary analyses, include limited uncertainty and sensitivity analyses, and make little attempt to present the results of these analyses in comprehensive way” (p. 7).

To successfully communicate uncertainty, EPA programs and offices need to develop communication plans that include identification of stakeholder values, perceptions, concerns, and information needs related to uncertainty about the decisions to be made and to the uncertainties to be evaluated. As discussed in Chapter 5, the development of those plans should be initiated in the problem-formulation phase of decision making, and it should continue during the assessment and management phases.

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