A Life Cycle and Cost Analysis of Preemptive Mitigation, Site Characterization, and Vapor Source Reduction Strategies at Industrial VI Sites with Multiple Buildings March 23, 2015 – USEPA Vapor Intrusion Workshop AEHS 25 th Conference on Soil, Water, Energy, and Air, San Diego, CA Loren Lund, Christopher Lutes, and John Lowe – CH2M HILL

2 Objective and Method Objective: Determine if preemptive mitigation is most effective strategy at industrial sites with multiple buildings Method: Quantitative Decision Analysis –Define alternatives 1.Preemptively mitigate all buildings 2.Characterize all and mitigate a few 3.Characterize, mitigate a few, and remediate source –Define criteria for making decision –Experts objectively score how well alternatives achieve criteria –Stakeholders subjectively weight importance of criteria –Scores and weights combined for overall values for each alternative –Overall values compared with life cycle costs

3 Results and Conclusions Investigate all, mitigate VI and reduce VOC source at a few buildings was optimal strategy considering value/cost Preemptive mitigation with limited site characterization may not be optimal strategy at sites with multiple buildings Method allows consideration of multiple decision criteria Stakeholder subjective weights depend on their preferences It is important to consider applicable scenarios, suitability, and sustainability prior to preemptively mitigating MMMM