Ghost Minesweeper Removed: Delta Cleanup Clears 400 Tons of Oil-Soaked Wreckage

In a major environmental breakthrough, a decaying naval relic — the HMCS Chaleur, a 140-foot wooden-hulled minesweeper — was finally removed from California’s Sacramento–San Joaquin Delta, ending decades of pollution, navigational hazard, and ecological risk.

Once a proud vessel of the Royal Canadian Navy in the 1950s, the Chaleur had long outlived its service. Abandoned in Little Potato Slough near Stockton, its oil-soaked structure and rotting wood posed significant threats to water quality, local fish species, and surrounding ecosystems. This month, a Coast Guard-led operation reached a historic milestone by completely dismantling and hauling away the ghost ship.

Why was the minesweeper removal so critical to the Delta’s safety?

The removal of the minesweeper wasn’t just about clearing a visible wreck — it was about removing an environmental ticking time bomb. As the vessel decayed in the slough, it leaked oil and other toxic materials directly into the Delta’s waters — a critical hub supplying fresh water to over 27 million Californians and irrigating farmland throughout the Central Valley.

In July 2025, Power Engineering Construction, working under the U.S. Coast Guard and funded by the Oil Pollution Liability Trust Fund, initiated a 25-day demolition project. A crane barge and underwater dive team were deployed to cut the hull into sections for safe removal. The operation, finalized on July 18, successfully extracted over 400 tons of oil-saturated wreckage, 400 gallons of oil products, 500 feet of contaminated boom, and a large volume of hazardous waste.

This marks the first time in years that Little Potato Slough is entirely free of large sunken vessels.

What happens next after the Chaleur minesweeper cleanup?

While the removal of HMCS Chaleur is a major win, it’s just the beginning. The broader Sacramento–San Joaquin Delta still contains dozens of derelict vessels—each posing similar risks to water quality, boating safety, and ecological health.

According to Lt. Cmdr. Mark Leahey of the U.S. Coast Guard, future efforts are underway to tackle these high-priority wrecks. Local environmental groups and state agencies are being brought into the fold for coordinated cleanup strategies targeting vessels in the worst condition.

This public-private cleanup model, which blends government funding with experienced marine contractors, could serve as a new standard for addressing neglected maritime hazards across the U.S.

The legacy of the HMCS Chaleur and its environmental toll

The HMCS Chaleur wasn’t always a hazard. Built in the 1950s for the Royal Canadian Navy, this wooden-hulled minesweeper served for decades before falling into private hands and eventual neglect. Over time, with no upkeep or accountability, the ship’s condition worsened, turning it into an unofficial dumpsite and oil leak source.

Marine experts and locals have expressed relief and optimism now that the wreck has been removed. Environmental watchdogs had long cited the Chaleur as one of the most toxic vessels in the Delta, calling for its extraction since the early 2010s.

Its removal signals a shift toward proactive environmental stewardship, showcasing how government-backed intervention and public interest can successfully reverse years of degradation.

Why it matters for California and future marine policy

This cleanup highlights the urgent need for national policies on abandoned maritime vessels, especially in environmentally sensitive zones like the Sacramento–San Joaquin Delta. With over 1,300 miles of interconnected waterways, the Delta plays a vital role in California’s water system, agriculture, and biodiversity.

Allowing derelict ships to linger threatens everything from salmon populations to farm irrigation systems. The Chaleur’s removal has reignited policy discussions around marine liability, ownership enforcement, and long-term funding for vessel remediation programs.

Local communities, tribal governments, and environmental nonprofits are now calling for enhanced legislation to prevent future ship abandonments and to speed up the cleanup of current wrecks.

With this historic minesweeper removal, California has not only eliminated an ecological hazard but also charted a clearer course toward a cleaner, safer Delta.

For your information:

What was the HMCS Chaleur?
The HMCS Chaleur was a 140-foot wooden-hulled minesweeper built in the 1950s for the Royal Canadian Navy. It was later abandoned in California and became an environmental hazard.

Where was the minesweeper located before removal?
It was stranded for decades in Little Potato Slough, near Stockton in California’s Sacramento–San Joaquin Delta.

Why was the Chaleur considered dangerous?
The vessel was leaking oil, rotting, and releasing hazardous materials into the water, endangering wildlife and water quality.

How was the minesweeper removed?
A Coast Guard contractor used a crane barge and divers to dismantle the ship in sections. The wreck was removed in July 2025 after 25 days of demolition work.

What environmental impact did the removal have?
The cleanup extracted 400+ tons of oil-saturated wreckage, removing a major pollution source and restoring safer navigation in the Delta.

Will more derelict ships be removed?
Yes. The Coast Guard plans to prioritize the removal of similar vessels across the Delta using government funding and local partnerships.