Environmental Due Diligence

Used Oil and Solvent Facilities
Multiple Locations

Services Provided


Trihydro partnered with a Fortune 500 waste management firm and local environmental health & safety managers to rapidly evaluate the potential liability associated with purchase of former used oil and solvent facilities. The goal of this project was to quickly identify potential environmental issues (historical and current), and provide detailed and accurate cost estimates for addressing identified issues for the purposes of adjusting the purchase price. Two-person teams visited each site along with at least one client representative to conduct 12 Phase I Environmental Site Assessments (ESAs); including conducting interviews with the current facility personnel while maintaining the confidential nature of the visit. Sites with potential environmental impacts were further investigated within two weeks of the Phase I ESA site visit as part of a Phase II ESA, including:
  • Collection soil boring samples
  • Installation of temporary groundwater wells
  • Collection of PCB wipe samples
  • Completion of EM-61 geophysical surveys of two sites with possible buried tanks and/or drums
Secondary containment measurements were also recorded to evaluate SPCC compliance. Environmental concerns that were identified included wide-spread TPH impacts to soil, possible buried tanks and drums, off-site groundwater impacts, and possible surface water impacts.

After the purchase was completed in 2009, Trihydro was retained to provide environmental engineering services at one of the facilities located in Louisiana. Test pits were used to evaluate the identified geophysical anomalies at the site. Additional soil sampling was conducted, along with removal of several subsurface oil/water separators identified as part of the geophysical survey, including one undocumented tank. A risk evaluation was conducted pursuant to the Louisiana Risk Evaluation and Corrective Action Program (RECAP) to develop site-specific standards. As part of the RECAP process, Trihydro characterized the site groundwater as a low-use non-drinking water source through completion of multiple aquifer slug tests and collection of geotechnical parameters. After soil characterization activities were completed, a Corrective Action Plan was prepared and approved to address groundwater through a low-cost monitored natural attenuation program.  

Based on recent improvements in groundwater quality, LDEQ recently approved no further action in 2014. Trihydro and the client are currently working with the LDEQ to finalize the Basis of Decision document for the facility.
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Negotiating with the LDEQ to obtain a Class III groundwater classification was key in obtaining closure at one of the sites since it was previously assumed to have Class II groundwater.  In situ data loggers were deployed by Trihydro’s geologists to record fluid level elevations during slug tests from six wells as part of the technical demonstration.