How a WWII Factory Became a Modern Australian Suburb

St Marys & Ropes Crossing: The Hidden History Beneath the Surface

When driving through the rapidly developing suburbs of Jordan Springs and Ropes Crossing, it might be hard to imagine the wartime secrets buried beneath their streets. However, hidden under these modern communities lies the legacy of Australia’s largest surviving World War II munitions facility — the St Marys Munitions Factory.

Thelma May Casey packing .303 light ammunition at St Marys Munitions Filling Factory in 1943. St Marys was the final factory in a process of munitions production where components from explosives, cartridge, propulsion and projectile factories were combined to make the final product. (Source: Australian War Memorial)

Workers filling shells at the re-opened St Marys Munitions Filling Factory c1962. Reopened in 1957, the St Marys facility was upgraded to process new types of munitions including aerial bombs, detonators and caps. (Source: Australian War Memorial)

A Wartime Giant: The St Marys Munitions Factory (1942–1945 and Beyond)

Established in 1942 during the peak of World War II, the St Marys Munitions Factory sprawled across hundreds of hectares and was a critical component of Australia’s wartime manufacturing effort. Located west of Sydney, this complex was strategically developed with safety and functionality in mind. Bunkers, trenches, and underground tunnels were engineered to store and manufacture explosive materials — including flame floats for the RAAF.

To support its operations, the site featured distinct zones — the Administrative Area and the Pyrotechnic Area, each equipped with its own fire station. Workers lived in nearby staff cottages, and the entire area buzzed with industrial activity until the war ended in 1945.

Following the war, the land transitioned into the Dunheved Industrial Estate, and later developments gave rise to what we now know as St Marys Industrial Estate.

Plan of the site showign cultural landscape features from the munitions and storage phase (1950s to 1990s). Source: Wianamatta Regional Park conservation management Plan.

Ropes Crossing: A Suburb with a Subsurface Past

The suburb of Ropes Crossing, located just east of the industrial estate, is part of this transformation story. Built over sections of the former munitions area, the land was once riddled with trenches, storage facilities, and potentially, buried contaminants. Although redevelopment and modern planning have revitalized the area, questions about the legacy of industrial use and land stability remain.

In recent years, reports of land sinking and structural damage in parts of Ropes Crossing have raised alarm bells. While the exact causes vary — from soil conditions to underground remnants — it underscores the importance of thoroughly understanding what lies beneath.

Aerial Imagery 1970 (source: Land Insight)

Ropes Crossing today (Google Earth Pro)

St Marys has also been associated with landfill activities, though these are separate from its history as a munitions manufacturing site.

Post-War Land Use – Emergence of Landfills

After the decline of the munitions activities, some parts of western Sydney — including areas near and around St Marys, Dunheved, and North St Marys — were used for landfill operations, particularly in the mid to late 20th century. These landfills were generally municipal waste facilities, often unregulated by today’s standards.

• Former quarries and low-lying land were commonly repurposed as rubbish tips or fill sites.

• Unregulated or legacy landfills near industrial zones in western Sydney were common, especially during the post-war urban expansion.

• Documentation is often limited, especially for landfills that ceased operation before modern environmental regulations came into effect (i.e., pre-1990s).

This means it is entirely possible that certain parts of the broader St Marys region, particularly near industrial and undeveloped fringes, were used as informal or municipal landfill sites.

Plan of the site showign cultural landscape features from the explosives and filling phase (1941 to 1946). Source: Wianamatta Regional Park conservation management Plan.

Why Historical Land Use matters

At Land Insight, our research spans the entire country — identifying current and historical Potentially Contaminating Activities (PCAs), such as:

• Former munitions and military sites

• Landfills (regulated and unregulated)

• Gasworks, mines, and quarries

• Industrial and commercial operations

• UXO (unexploded ordnance) risk areas

  
  

Our comprehensive database ensures that every Land Insight Environmental Risk Report  includes not just current hazards, but also the historical land use footprints that could affect property safety, environmental health, and investment value.

Why should you care?

Whether you are a developer, homebuyer, or environmental consultant, knowing that your site sits on a former munitions factory, landfill, or industrial estate can influence:

• Foundation stability and construction costs

• Soil and groundwater contamination risk

• Insurance and legal liabilities

• Long-term property value and health risks

Places like St Marys and Ropes Crossing are cautionary tales — not of doom, but of due diligence. Past uses of land shape future risks, and understanding these stories helps ensure we build safe, resilient, and informed communities.

How can you confirm specific historical Land Use in St Marys?

• NSW EPA’s Contaminated Land Register

• Local council environmental or planning records (Penrith City Council)

• Historical aerial imagery and land zoning overlays (can be provided by Land Insight)

• Land Insight’s hazard database, which includes landfill mapping and historical land use scans

References and Sources:

• NSW War Memorials Register – St Marys Munitions Factory. Australian Department of Defence – Contamination and UXO risks. Penrith City Council Local Environment Plan (LEP). NSW EPA – Contaminated Land Guidelines.

  Lost Sydney: St Marys Munitions Factory