UPSS Abandonment In‑situ via Foam Filling — Hervey Bay, QLD

Project overview

iEnvi was engaged by the owner of a restaurant site listed on the Queensland Environmental Management Register (EMR) to manage the decommissioning and abandonment of three underground storage tanks (USTs). The tanks were historically associated with a commercial service station use. Existing building structures overlaid parts of the tanks, which prevented safe removal without compromising onsite buildings. The chosen method for decommissioning was in‑situ abandonment by foam filling.

Why foam filling (in‑situ abandonment) was used

• Building constraints: Structural obstruction prevented excavation and physical removal of the tanks without impacting the building.
• Regulatory alignment: In‑situ abandonment via foam filling is an accepted technique where removal is impractical, provided the process and materials meet applicable standards and are documented.
• Practical outcome: Foam filling reduces the risk of future collapse, water pooling inside the tank, and provides a permanent fill that simplifies future site use.

Compliance and deliverables

iEnvi managed and completed the abandonment works and prepared documentation outlining compliance with AS4976‑2008 (Decommissioning of underground petroleum storage systems). Delivered outputs included:

• Records of the foam filling process and materials used.
• Documentation demonstrating the method met relevant sections of AS4976‑2008 for abandonment where removal was impractical.
• Advice on further works required to seek removal from the QLD EMR, specifically validation groundwater monitoring and completion of a UPSS (Underground Petroleum Storage System) report.

Next steps to progress EMR removal and transaction readiness

Abandonment is an important compliance step but not the only requirement for EMR removal. Typical follow‑up works iEnvi recommended include:

1. Validation groundwater monitoring (to demonstrate no ongoing groundwater impacts from the historic UPSS).
2. Completion of a formal UPSS report and submission to the regulator, addressing historic contamination, current risk, and the abandonment methodology.
3. Remediation or management actions if monitoring identifies residual contamination.

Practical takeaways for owners and developers

• Time and approvals: In‑situ abandonment is usually quicker and less disruptive than full tank excavation, but regulators will expect documentation and validation monitoring before a site can be removed from registers.
• Cost implications: Foam filling avoids building demolition costs and can reduce immediate remediation expenditure. Expect costs for monitoring and reporting to demonstrate closure and support regulatory removal.
• Risk management: Properly documented in‑situ abandonment lowers long‑term liability and simplifies future redevelopment once validation requirements are met.

Contact iEnvi

For a confidential discussion about UPSS abandonment, EMR removal or validation monitoring, call 13000 43684 or contact us.