Vapor Intrusion Assessment

In 2005, after more than 20 years of remediation and monitoring efforts, a contaminated site in Fairbanks, AK was conditionally closed with institutional controls that restricted residential use of the apartment building at the site. In 2024 Fairbanks Environmental staff developed a workplan for indoor air and sub-slab soil gas sampling using passive air samplers to investigate the potential vapor intrusion exposure pathway. FE staff conducted a site survey and collected indoor air and sub-slab soil gas samples in accordance with the work plan during winter conditions. Sample results demonstrated that vapor intrusion was not occurring, and that the lower level of the apartment building was safe for residential use. A report documenting the findings was provided to the Alaska Department of Environmental Contamination (ADEC), resulting in the modification of institutional controls to allow residential occupation of the space in early 2025.