1250 Madison

Background

1250 Madison is the site of a former service station with orphaned leaking underground storage tanks (LUST). The site was left contaminated from reported releases in December 1998 and August 1999. The Department of Environment, Great Lakes and Energy (EGLE) retained ERG to conduct a series of investigations and corrective action activities at the Site. The work was performed under the Indefinite Scope Indefinite Delivery (ISID) contract between EGLE and ERG. 

The Challenge

In 2017, ERG installed a series of soil borings, groundwater monitoring wells (MWs), soil gas wells, and sub-slab vapor points (VPs) within the health clinic building on-site and within the adjacent off-site commercial structure. ERG commenced a quarterly soil gas and ambient indoor air sampling program with 12-hour summa canisters. 

Throughout the sampling process, chlorinated hydrocarbons were observed beneath the off-site building. Due to high concentrations of chlorinated hydrocarbons beneath the off-site building, EGLE-RRD contracted ERG to solve the issue. 

ERG’s Solution

ERG designed and installed a soil gas mitigation system and completed performance testing. Between October 2017 and February 2021, ERG installed two (2) sub-slab depressurization (SSD) systems under the existing off-site building with minimal structural disturbance to achieve full coverage of the building’s subsurface footprint.

The SSD systems were designed to interrupt the vapor intrusion exposure pathway preventing undue exposure to the building’s occupants.

Client Results

• ERG’s SSD systems provided total coverage beneath the off-site structure to capture and mitigate the soil gas plume.

• ERG turned over the control system to the property owners in September 2021.

 SERVICES PROVIDED

Soil investigation

Groundwater investigation

Soil gas investigation

Soil gas monitoring

Due care planning

Vapor intrusion mitigation system design and implementation