Risk Assessment Challenges, Limitations, and Making Decisions to Save Lives

Deciding How to Protect n WHO? –Bystanders vs. employees –young vs. old –poor vs. rich n $ How Much? –$10,000 per life saved –$1,000 per life saved –small risk vs. no job

Risk n Technical –# of people that will be injured, get ill, or die n Non-Technical –Upsetting, frightening, or enraging

Risk Assessment: Technical n Hazard Identification n Dose-Response n Exposure Assessment n Aggregate Risk Assessment (risk to whole population)

Hazard Identification n Toxicology –animal studies –High doses n Epidemiology –Uses statistics to “factor out” multiple variables –large effect –large sample size

Chance & Probability n Demonstrates two important concepts in epidemiology & statistics: –Sample size –# of variables

Risk Assessment: Technical n Hazard Identification n Dose-Response n Exposure Assessment n Aggregate Risk Assessment (risk to whole population)

Exposure Assessment n Have idea of how much causes harm n Want to know exposure levels –environmental measure X time = dose guess –direct measurements rarely available

Aggregate Risk Assessment n Risk to the whole population –Census data –Surveys n Individual Risk vs. Societal Risk

Aggregate Risk Assessment n Individual –1 death per 100 people –300 people exposed –Serious for those 300 people –Small risk for the whole population n Societal –1 death per 100,000 –Small individual risk –250 million exposed –Greater societal risk (2,500 deaths/year)

Risk = Hazard + Outrage (the non-technical side) n Voluntary vs. Involuntary n Natural vs. Industrial n Familiar vs. Exotic n Dreaded or Not n Source: The Reporters Environmental Handbook