Final Program - Society for Risk Analysis

sociated with model error. Second, predictions can be deconvolved to remove someof the uncertainty about predictions associated with the measurement protocol. Inboth of these cases, the structure of errors can be characterized as a distribution orp-box with arbitrary complexity. We illustrate the requisite calculations to make thesecorrections with numerical examples. We conclude (1) the notion of ‘bias’ shouldbe understood more generally in risk analysis to reflect both location and uncertaintywidth, (2) self-interest bias and understatement of uncertainty are common, large inmagnitude, and should not be neglected, (3) convolution can be used to inflate uncertaintyto counteract human psychology, and (4) deconvolution can be used to removesome of the uncertainty associated with measurement errors.W1-C.4 Finkel AM, Altemose B, Hattis D; afinkel@law.upenn.eduUniversity of Pennsylvania Law SchoolNONE OF THE OCCUPATIONAL EXPOSURE LIMITS REVEAL RISKINFORMATION: A QUANTITATIVE “NUDGE” COULD SAVE LIVESFor ambient air, water, and food, lists of the potencies of contaminants arereadily found, and derive from the two dose-response regimes in widespread use forthe past 30 years (continuous functions for presumed carcinogens, and “margins ofsafety” below low-risk levels for non-carcinogens). But by far the greatest exposuresto these substances occur in the workplace, where no authoritative body has set levelsthat rely on risk assessment techniques. In particular, the few Permissible ExposureLimits that OSHA has set may reference elaborate risk assessments, but ultimately areset based on (pessimistic) assumptions about feasibility; thus, every PEL reflects a differentrisk level. The ACGIH Threshold Limit Values (TLVs) reflect expert judgmentin light of extensive toxicologic and/or epidemiologic evidence, but employ no riskassessment techniques, and incorporate almost as many different implicit “margins ofsafety” as there are TLVs. Ready access to scientific knowledge about the relationshipbetween exposure and risk should not be hidden from those exposed. Therefore, weoffer a detailed proposal for government and academia to collaborate to generate thefirst list of (roughly several hundred) “risk-based exposure goals” for the workplace.Each exposure goal would correspond to a common probability of harm (we suggest1-in-1000 excess working-lifetime risk), based on common computational methodsand common ways to handle uncertainty. We recommend a “unified” paradigm thattreats non-carcinogenic endpoints as having estimable non-zero risks at the populationlevel, in the spirit of the recommendations in the recent Science and Decisionsreport of the National Research Council. We will discuss the value of such a compendiumof exposure goals for right-to-know and product substitution purposes,and expore how OSHA could change its inspection and enforcement policies to encourageemployers to achieve acceptable risk levels, even though the guideline levelswould be unfettered by information about the aggregate costs of any specific controlmeasures.W1-H.3 Fischbach JR, Ortiz DS, Johnson DR, Burger NE; djohnson@rand.orgRAND CorporationASSESSING LONG-TERM FLOOD RISKS TO COASTAL LOUISIANAUNDER DEEP UNCERTAINTYLouisiana is in the midst of updating its Master Plan for a Sustainable Coast,which specifies a set of structural protection projects to be implemented over thecoming decades to protect coastal communities from the effects of catastrophic hurricanes.These projects need to be evaluated on a variety of criteria but primarily onthe extent to which actions will reduce risk from flooding. We have developed theCoastal Louisiana Risk Assessment Model (CLARA) to evaluate this risk under awide range of uncertain scenarios about future regional growth; sea level rise andsubsidence; and nonstationarity in future hurricane characteristics. CLARA is a downscaledversion of previous models developed by the Interagency Performance EvaluationTask Force (IPET) and Louisiana Coastal Protection and Restoration project(LACPR). The model is designed to be useful for long-range planning over a 50 yeartime horizon and large-scale scenario analysis rather than design-level analysis. Toflexibly compare the risk reduction achievable by many potential projects, we havedeveloped innovative methods for storm sampling and the estimation of flood levelsinterior to a protection system based on the probability distributions of surge levelsat points along the exterior of the system. These provide the computational and statisticalefficiency that allows evaluation of many scenarios within feasible limits oncomputing resources. The model incorporates system fragility by estimating the probabilityof multiple modes of failure, and we also consider the impact of nonstructuralmitigation policies such as floodproofing, home elevation and buyouts. Flood depthsand residual economic risk are reported as 50-, 100-, and 500-year exceedance values.We discuss these new methodologies and present key insights from model results.M3-J.1 Fitzpatrick JW, Ohanian EV; fitzpatrick.julie@epa.govUS Environmental Protection AgencyU.S. ENVIRONMENTAL PROTECTION AGENCY RISK ASSESSMENTFORUM ACTION PLAN FOR ADVANCING HUMAN HEALTH RISKASSESSMENTIn response to recommendations from the National Research Council (NRC)reports Science and Decisions, Phthalates and Cumulative Risk Assessment, and ToxicityTesting in the 21st Century, and considering the Agency’s cross-cutting fundamentalstrategy of working for environmental justice and children’s health, the RiskAssessment Forum hosted a Human Health Risk Assessment Colloquium in October2010. The Agency only Colloquium brought 120 risk assessors and risk managerstogether to develop an Action Plan to Advance Human Health Risk Assessment.Colloquium discussions focused on, Agency senior managers risk assessment needsfor decision making, uncertainty and variability, dose-response assessment, use of97