Communicating Quantitative Information About Unexploded Ordnance Risks to the Public

• Published in: Environmental science & technology 2013-05, Vol.47 (9), p.4004-4013
• Main Authors: Gibson, Jacqueline MacDonald, Rowe, Aimee, Stone, Eric R, Bruine de Bruin, Wandi
• Format: Article
• Language: English
• Subjects: Air. Soil. Water. Waste. Feeding; Biological and medical sciences; Communication; Communication. Information transfer; Environment. Living conditions; Exact sciences and technology; Explosive Agents; Graph representations; Histograms; Information and communication sciences; Information science. Documentation; Land use; Library and information science. General aspects; Medical sciences; Military base closures; Military bases; Probability; Public health. Hygiene; Public health. Hygiene-occupational medicine; Public Sector; Risk Assessment; Risk management; Sciences and techniques of general use
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es305254j

Military base closures have left 600,000 acres of U.S. land contaminated with unexploded ordnance (UXO). Recent research has demonstrated a method for quantifying the probability of residual UXO harming future land users. Here, we explore how a community neighboring a closed, UXO-contaminated military base responds to the probabilistic risk information this method produces. We explore how probabilistic information affects their risk understanding, risk management preferences, risk perceptions, and worry. We test eight different communication formats employing varying combinations of textual risk descriptions, comparative risk information, stacked bar graphs illustrating the proportion of future land users at risk, and textual summaries and/or graphical histograms presenting uncertainty. We find that stacked bar graphs double the odds of correctly reporting the probability of harm and decrease the perceived risk, compared to textual descriptions. Providing histograms or summary uncertainty information decreases the odds of correctly reporting the probability of harm by about one-half, compared to communications without uncertainty information. We also find that risk communication formats do not alter risk management preferences. We recommend that as EPA reevaluates its UXO risk management policies in the coming year, the agency shift to quantitative rather than its current qualitative approach to assessing and communicating UXO risks.