Environmental Project

Colorado’s Most-Valuable Brownfields Redevelopment Project

Commercial and Residential Developer Denver, CO

Solution Overview

Client:

Commercial and residential developer

Business Challenge:

  • 57-acre former rubber factory
  • Complex contaminant mix
  • Intense stakeholder scrutiny

Solution:

  • Regulatory negotiations
  • Characterization and drilling
  • In-situ remedy implementation
  • Sampling and waste identification
  • Phase II investigation
  • Voluntary Cleanup Program (VCP) application

Results:

  • Identification, removal, and disposal of ~19K cu. yd. of contaminated soil and asbestos
  • Cost-effective remedial approach
  • Accelerated remedial timeframe
  • Received regulatory No Action Determination (NAD) allowing initiation of redevelopment for mixed commercial and residential use

Photo Credit: Plazak at English Wikipedia.

Challenge

Arguably the most-valuable Brownfields project in Colorado, the Former Gates Rubber Factory covers 57 acres in the heart of the City of Denver. Our client depended on Apex Companies to navigate this high-profile redevelopment project through intense stakeholder scrutiny due to its size, proximity to the South Platte River, and long industrial history. The site has a complex contaminant mix of chlorinated solvents, petroleum NAPL, and emerging chemicals of concern from several sources.

Solution

Apex partnered closely with the property owner during regulatory negotiations with the Colorado Department of Public Health and Environment (CDPHE) and provided technical oversight throughout the project. Apex also directly performed site work across the full spectrum of environmental management, from characterization and drilling, to excavations, to in-situ remedy implementation, to performance sampling and extensive waste identification, and management during site redevelopment.

The site had been dormant for a decade, despite its valuable location, due to the complex bedrock lithology, chlorinated solvent contamination, and presence of emerging chemicals of concern. Apex directed a fresh Phase II investigation using innovative subsurface imaging technology and a discerning review of older characterization data. The updated conceptual site model revealed dominant pathways for contaminant movement and risk exposure that completely changed the regulatory view and previously-scoped remediation needs. The result was a far more cost-effective remedial approach and accelerated remedial timeframe. Apex then negotiated a new risk-based cleanup approach with state and municipal regulators, authored the Voluntary Cleanup Program (VCP) application, and oversaw implementation of the remedy.

Results

Apex supervised the large-scale enhanced reductive dichlorination (ERD) in-situ remedy for chlorinated solvent impacts to soil and groundwater across the site. The remedy included several rounds of ERD injections to target two primary source areas, and satellite injections for disconnected portions of the plume. Apex also performed two complex excavations (totaling approximately 4,500 cubic yards) among remaining building foundations to remove unsaturated soils with residual NAPL and impacts from chlorinated solvents.

Apex worked with the property owner during numerous negotiations with regulators, authored decision documents, and prepared a series of CDPHE-approved No Action Determination (NAD) requests, development lot by development lot, as portions of the property were remediated. The last of the redevelopment parcels received regulatory NAD in November 2017, allowing the initiation of redevelopment for mixed commercial and residential use.

On behalf of the property owner, Apex managed general compliance with the site’s Materials Management Plan (MMP) by all contractors during site redevelopment, which included the excavation of 14 acres of former buried buildings and their concrete foundations, totaling approximately 130,000 cubic yards. Apex also conducted environmental testing, segregation, and management of hazardous and non‑hazardous materials that were exposed at this long‑time industrial facility.

Apex’s team of environmental engineers, certified asbestos building inspectors (CABIs), and abatement subcontractors worked with the developers to identify, properly remove, and dispose of approximately 19,000 cubic yards of regulated asbestos-contaminated soil (RACS) and asbestos in demolished structures.

Today, the site is one of the most marketable redevelopment districts in Denver. Labeled Midtown/Broadway Station due to its close proximity to the Broadway Light Rail Station, the transit friendly site will support a mix of residential, commercial, and recreational uses. We are excited to see what the future will bring for this high potential site, and are proud to have been a partner in its redevelopment and return to beneficial use!

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