According to Professor Donald Rothwell, a specialist in international law at the Australian National University, Australia may face legal obligations under international law if ExxonMobil proceeds with plans to leave decommissioned oil structures in Bass Strait.
Bass Strait, a critical corridor for international navigation, holds special status under the United Nations Convention on the Law of the Sea (UNCLOS) and associated International Maritime Organisation (IMO) guidelines.
As a convention signatory, Australia is required to remove structures from the strait once they are no longer in use.
ExxonMobil, decommissioning its 50-year-old Gippsland Basin facilities up to 77 kilometers off Victoria’s coast, proposed leaving lower sections of steel structures on the seabed at depths beyond 55 meters.
In September, the company indicated that these structures would only be removed as part of future decommissioning unless the regulator, the National Offshore Petroleum Safety and Environmental Management Authority (Nopsema), approves an alternative solution.
ExxonMobil’s proposed decommissioning plan raises concerns about taxpayer-funded cleanups if environmental obligations aren’t strictly enforced.However, Rothwell’s analysis suggests Australia has a clear responsibility to enforce the full removal of infrastructure under UNCLOS.
The Wilderness Society, which sought Rothwell’s legal opinion, has urged Nopsema to enforce Australia’s international obligations strictly.
Fern Cadman, a Wilderness Society campaigner, highlighted concerns that taxpayers could be burdened with cleanup costs if ExxonMobil, or other corporations, lack the financial means to comply in the future.
As Australia’s first major offshore development, the Gippsland Basin project underscores the country’s growing challenge with oil and gas decommissioning.
Over the next three decades, an estimated 5.7 million tonnes of material—equal to 110 Sydney Harbour bridges—will need removal from offshore facilities, according to the Centre of Decommissioning Australia.
ExxonMobil plans to finalize its decommissioning submission by 2025, marking a potential test of Australia’s commitment to UNCLOS and its environmental obligations.