Proposed Cleanup Grant

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The City of Mason City, supported by EPA Brownfields Assessment Grant funding, completed a full suite of environmental due diligence activities at Mohawk Square to understand site conditions and responsibly plan for future cleanup and redevelopment. This effort included a Phase I Environmental Site Assessment (ESA), a Phase II ESA, and a building-wide Asbestos‑Containing Materials (ACM) inspection, together providing a clear picture of environmental risks, regulatory needs, and next steps.

The Phase I ESA established the historical and environmental context of the property. Through records review, site reconnaissance, and regulatory database searches, the assessment identified a nearby former auto repair and fueling operation as a Recognized Environmental Condition (REC) with the potential to have affected the property. The report also noted the presence of hazardous building materials and widespread water and mold damage inside the long‑vacant structure, highlighting the need for further evaluation prior to redevelopment.

The Phase II ESA directly investigated these concerns by collecting soil and soil vapor samples to evaluate potential petroleum‑related impacts. Due to shallow bedrock, groundwater was not encountered; however, laboratory analysis of soil and vapor samples found no exceedances of Iowa Department of Natural Resources (IDNR) statewide standards or EPA vapor intrusion screening levels. Risk evaluations using EPA VISL and IDNR cumulative risk tools concluded that detected concentrations pose no unacceptable cancer or non‑cancer risks for future residential or commercial use, and no further environmental investigation was recommended.

The ACM Inspection provided a detailed inventory of asbestos‑containing materials throughout the 215,000‑square‑foot building. Inspectors collected nearly 300 samples and confirmed asbestos in multiple materials, including floor tiles and mastics, pipe insulation, ceiling texture, wall adhesives, and other miscellaneous building components. The findings confirm that regulated asbestos abatement will be required prior to any structural demolition or renovation activities, ensuring the protection of workers, the community, and the environment.

Together, these three assessments give the City and future developers a complete, science‑based understanding of environmental conditions at Mohawk Square. This comprehensive due diligence approach reduces uncertainty, clarifies regulatory obligations, and positions the site for safe, strategic cleanup and long‑term redevelopment.

Prior to applying for an EPA Brownfields Cleanup Grant, The City of Mason City prepared an Analysis of Brownfields Cleanup Alternatives (ABCA) for Mohawk Square.  Three cleanup options were evaluated: no action, partial abatement of friable ACMs, and full abatement of all ACMs. After considering effectiveness, feasibility, and cost, the recommended approach is to full abatement of all ACMs to allow for future redevelopment for residential use. This option permanently eliminates health risks and aligns with the City’s long-term vision for redevelopment of the property.