A plan by oil and gas giant Chevron to create artificial reefs out of decommissioned oil platforms off Western Australia's Pilbara coast has drawn the ire of unions and green groups.
The company owns nine platforms in the waters around Thevenard Island, off the coast of Onslow, but has not extracted oil from the area since 2014.
Chevron must decommission the infrastructure, but has received state government approval to convert the rigs into artificial reef environments.
While all eight platforms will be repurposed, five will remain in place, with three to be temporarily removed before being reinstalled at the site.
The ninth platform will be fully removed and recycled on the mainland.
Chevron, the government and fishing body RecFishWest say the plan is ecologically safe, arguing it will benefit the local marine ecosystem and provide fishing and tourism opportunities.
However, a national environment group says Chevron is shirking its responsibilities, and the plan sets a poor precedent as decommissioning ramps up across Australia.
Oil operations were also based onshore at Thevenard Island, but they have been removed and rehabilitation of the landscape is continuing.
The federal government has predicted an industry around decommissioning oil and gas infrastructure in Australian waters could be worth up to $60 billion over the next 30 to 50 years.
A number of similar "rigs to reef" projects already exist in WA waters.
Thevenard Island's artificial reefs would be managed by RecFishWest and the state's Department of Primary Industries and Regional Development once completed, under approval from the federal government's Environment Protection (Sea Dumping) Act.
But Wilderness Society fossil fuel campaigner Fern Cadman said the project was an attempt by Chevron to reduce the financial cost of cleaning up its operations.
"The long and the short of it is cleaning up oil and gas infrastructure is expensive," she said.
"So companies are looking for ways they can minimise the cost."
Ms Cadman said she was also concerned about heavy metals and chemicals leaking from the infrastructure and polluting the surrounding environment.
"The question we should be asking is whether oil and gas infrastructure, which was never intended to be a substitute for marine ecosystems, should be being used in that way," she said.
"We are concerned that this project slipping through without proper environmental scrutiny could then set a precedent for other similar proposals."
A Chevron spokesperson said the company would "fully account" for decommissioning and would only return infrastructure to the state once it had achieved the "agreed end state".
"Chevron Australia has a proactive and planned approach to decommissioning, with the highest priority placed on the safety of our people and the environment," the spokesperson said.
Thevenard Island is also home to tourism operator Mackerel Islands, which offers accommodation and outdoor experiences for keen fishers and wildlife lovers.
Chief executive Drew Norrish said the company had major expansion plans now Chevron was winding down.
He said while he understood the environmental concerns, he backed the plan.
"It's just an enhancement of what's already there rather than changing or adding something that's significantly different," he said.
"I think it's just nothing but positives from our side."
RecFishWest and Chevron said community consultation had informed large parts of the plan.
The proposal has also been criticised by the Offshore Alliance, the union representing workers on oil and gas platforms.
Organiser Doug Heath said leaving infrastructure around Thevenard Island would take jobs away from workers who would otherwise be involved in full removal.
"It's not a good start to what's going to be 30 years of decommissioning if government are going to chop up the jobs of our members," he said.
"It doesn't pass the pub test for the WA government to sit down with Chevron, to the exclusion of other stakeholders, and cut a deal."
A state government spokesperson said the union had been included in consultations around decommissioning policy, and said it welcomed any ongoing feedback.
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