MITIGATING OTHER’S MESSES: A BROWNFIELDS CASE STUDY

Brownfields Cleanup Programs are a vital regulatory agency within state environmental agencies, working cooperatively with property owners who did not create the environmental problem they are voluntarily paying to remediate. They also pose many challenges: issues are often discovered during a real estate transaction, resulting in a seller, purchaser, and potentially separate tenants who all have a vested interest in the project. Property uses and building footprints change significantly over time. Pre-regulation chemical storage & disposal practices (with chemical types varying as property use changes) can result in multiple releases into the environment with comingled plumes. And if any of those chemicals are volatile in nature, health risks associated with vapors getting into buildings must be properly evaluated. Chemical Vapor Intrusion can be a challenge to characterize and mitigate at the simplest of buildings: place that structure on top of a historic mining facility and things get even more complex.

This case study follows the investigation & cleanup of historic trichloroethylene (TCE) impact at an active commercial factory located in the Tri-State Mining District of southwest Missouri. The onsite building was expanded several times in the 1950s through the 1980s. After discovery of impact, the site was enrolled in Missouri’s Brownfields Voluntary Cleanup Program (BVCP). Our journey to a certificate of closure for this site included historic aerial sleuthing to identify the expansion of the building over time; ground-penetrating radar (GPR) to locate former mine shafts beneath the building; soil, groundwater and subslab vapor investigations; extensive indoor air sampling; excavation to remove impacted soil; bioremediation through in-situ chemical injections; and the design & installation of a vapor mitigation system, all while balancing the needs of the former owners (our client) and trying to limit disruption of business to the current occupants and ensure their safety working in the facility.