Many of Australia’s coastal settlements expanded rapidly through the mid‑twentieth century, when waste management standards were minimal and foreshore land was commonly used for tips and land reclamation.

Hundreds of historic landfill sites - many now closed and poorly documented - are located along beaches, dunes, estuaries and low‑lying coastal margins.

As coastal erosion accelerates with sea‑level rise and more frequent extreme storms, these sites present a growing challenge for coastal councils

Unlike contemporary engineered landfills, historic coastal tips were typically unlined, heterogenous, and placed directly within dynamic coastal systems. As erosion exposes buried waste, materials can enter the beach, nearshore waters or adjacent wetlands, creating risks to public safety, ecosystem health, council assets, and regulatory compliance.

There is no national inventory of historic landfills, however state and local government investigations indicate they are widespread.

Some historic landfill sites can be reused in time for sporting fields and other recreation spaces. This can be an effective use of land that is otherwise limited land. However these sites can still impact environmental and human health that need to be managed, especially with risks of rising seas and saltwater intrusion.

Coastal landfills that are being affected by erosion or inundation can release:

• plastics, asbestos fragments, metals and construction debris onto beaches
• leachate containing nutrients, hydrocarbons, heavy metals, and emerging contaminants such as PFAS ('forever chemicals' because they persist 'forever')
• landfill gases that migrating into confined spaces or underground services.

Exposure pathways are often uncertain and episodic, making risk communication and management difficult for councils.

For coastal councils, eroding landfills create:

• unplanned remediation costs, often running into millions of dollars
• complex regulatory responsibilities, spanning waste, contaminated land, coastal protection and public land management
• reputational and legal risks, particularly where public access areas are affected.

These risks can be compounded where councils inherit responsibility for sites created by former authorities or private operators, without clear records or funding mechanisms.

Historic landfills are considered to be a legacy climate risk that require proactive identification and integration into coastal adaptation strategies. Practical steps include:

• systematic desktop and field investigations to locate historic sites
• inclusion of landfills in coastal hazard and asset risk registers
• early engagement between coastal, environmental health, and contaminated land teams
• realistic planning for long‑term adaptation limits, including scenarios where protection is no longer viable.