Rigs-to-Reefs: Retired Oil Rigs Are Becoming Artificial Reefs, But Critics Question the Tradeoff

The “Rigs-to-Reefs” push has seen thousands of oil drilling wells and platforms decommissioned and used to harbour marine life

Long after they stop pumping oil, hundreds of offshore rigs around the world are finding a second life beneath the waves as artificial reefs. Supporters argue that the shift enables marine ecosystems to recover from habitat destruction and climate change. But not everyone agrees that the “rigs-to-reefs” approach is a win for the environment.

Instead of fully dismantling decommissioned rigs, energy companies leave parts of the cleaned structures underwater, where fish, coral, and other marine life quickly take hold. Advocates say the practice helps boost biodiversity and create habitat in areas where natural reefs have been lost.

The U.S., Malaysia, Thailand, and Australia have all implemented rigs-to-reefs programs. In the Gulf of Mexico alone, more than 600 retired rigs have been converted into artificial reefs, according to the Bureau of Safety and Environmental Enforcement (BSEE), which manages the program under the Department of the Interior.

Rigs as Reefs

Offshore oil rigs are massive steel structures fixed to the ocean floor, sometimes rising hundreds of feet from the seabed. Once production ends, removing these platforms is costly and difficult. Full removal can disturb the marine life that has accumulated around the rig over the decades.

The rigs-to-reefs process involves removing hazardous equipment and pollutants like drilling mud and hydrocarbons. This cleans the structure and ensures it’s stable enough to remain underwater. In most cases, only the lower portion of the rig is left behind.

Studies from California suggest that some of these converted rigs support up to 10 times more fish biomass than nearby natural reefs. Marine life, including coral, barnacles, crabs, and dozens of fish species, quickly colonize the structures.

A typical eight-leg structure can provide habitat for 12,000 to 14,000 fish, and a four-leg structure can offer two to three acres of habitat for hundreds of marine species, according to BSEE.

In Southeast Asia, similar reefing programs have helped replenish fish stocks and promote tourism. In Malaysia, government officials say reefed rigs are boosting marine conservation and economic activity in coastal areas.

Oversight and Regulation

In the United States, the Rigs-to-Reefs program is managed by the BSEE in coordination with coastal state governments. Under its policy, BSEE allows partial platform removal when a structure meets the required criteria for reefing.

The agency works closely with state artificial reef programs to determine if a structure is a suitable candidate. Additionally, companies that participate in reefing may be eligible for reduced decommissioning costs, with savings often redirected to state-run reef maintenance and research.

BSEE Director James A. Watson emphasized the collaborative nature of the program, stating:

“For the past several months, we have been working with our federal partners, state officials, and affected stakeholders in the Gulf of Mexico region to learn about their needs and concerns regarding the inclusion of oil and gas infrastructure in the states’ artificial reef programs. This policy is reflective of the feedback we received. It provides states greater flexibility in their planning and addresses the multiple uses for these areas while ensuring the marine environment is protected”

Despite the rigorous process, critics worry that reefing offers oil companies a way to avoid the full expense and responsibility of complete removal.

Environmental Concerns of Rigs-to-Reefs

Environmental advocates warn that the long-term impacts of leaving structures in place remain unclear. Even after cleaning, traces of drilling fluids, heavy metals, and hydrocarbons may remain.

BSEE argues that it addresses these concerns through mandatory inspections and compliance tracking. Once a rig is reefed, it remains under long-term observation by state and federal agencies. Still, environmental groups urge more public transparency and independent assessments.

Others argue that while reefing might provide short-term habitat benefits, it could delay the oil industry’s full accountability for environmental restoration.

Differing Perspectives in Europe and Canada

While the U.S. leads in reefing programs, European countries have taken a more cautious stance. Many are bound by the OSPAR Convention, a treaty protecting the North-East Atlantic marine environment, which prohibits most offshore infrastructure from being left at sea.

Canada, though not an OSPAR member, has similarly avoided converting offshore rigs into reefs. Instead, it has focused on repurposing retired navy vessels as artificial reefs for scuba diving and marine habitat restoration. The HMCS Nipigon was sunk in 1998 off the coast of Ontario for this purpose, part of a broader trend that favors carefully controlled, non-industrial materials.

Rigs-to-reefs is part of a growing global movement to restore ecosystems by repurposing former industrial sites. In North America’s Great Lakes, abandoned waterfronts and shipping docks have been transformed into wetlands and fish habitats, offering a similar model of adaptation.

Rigs-to-Reefs: Climate Pressure and Future Potential

Artificial reefs may play a role in bolstering marine biodiversity, but they won’t be immune to climate-related changes. Rising ocean temperatures, acidification, and shifts in species distribution could stress these marine ecosystems, especially if coral and other sensitive organisms are unable to thrive on reefed rigs.

At the same time, the very presence of these underwater structures offers researchers a chance to study resilience.

For now, the debate over rigs-to-reefs continues. To some, the initiative is a smart compromise that allows turning relics of fossil fuel production into tools for marine recovery. To others, it risks allowing big polluters to deflect accountability for their past environmental damage.

Whether seen as environmental innovation or industrial workaround, old infrastructure has shown potential to play a meaningful role in building a healthier ocean. For hundreds of retired rigs now boasting huge living ecosystems beneath the surface, the rigs-to-reefs practice appears poised to continue growing.

Editor’s Note: The opinions expressed here by Impakter.com columnists are their own, not those of Impakter.com — In the Cover Photo: Drilling rigs in Cromarty Firth near Invergordon waiting to be dismantled, April 2022. Cover Photo Credit: Hannes Grobe.