Concentric Geoscience provided geo-environmental consultation associated with a 450 litre heating oil release from an exterior storage tank at a rural residential property near Cornwall, Ontario. The release resulted in heating oil entering the basement sump and discharging to a roadside ditch, extending impacts approximately 120 metres from the site. Emergency remedial measures involved a high-suction vacuum tanker truck and the diversion of petroleum-impacted sump water to a mobile granular activated carbon pump and treat system. A temporary shoring system in the affected area of the residence was required to remove the petroleum impacted rubble foundation wall and impacted soil underneath the residence. A phased approach was undertaken thereafter to reinstate the foundation and basement and then complete exterior excavation along the sump line from the residence, and in the source area of the release. Concentric Geoscience project personnel provided technical consultation and project updates to all stakeholders including the insurer, insured, affected neighbours and the MECP, throughout the assessment and remediation process.