Following a public comment period and consideration of the comments received, the publication RR-649, Guidance for Documenting the Investigation of Human-made Preferential Pathways Including Utility Corridors, is now posted and available online.
RR-649, formerly titled Guidance for Investigating Utilities, focused on investigating the migration of contamination in media along the exterior of utility corridors within the surrounding utility bedding. Current research indicates that contamination and vapors may migrate within utilities as well as other preferential pathways and the updated version of RR-649 reflects this new understanding. For additional information, please see the July 2020 Issues & Trends webinar, Vapor Intrusion: New Preferential Pathways, in the Remediation and Redevelopment Program’s training library.