Endangered turtles and ‘exceptional’ coral at risk from Woodside’s gas drilling in WA, watchdog says

The Browse gasfield project is Woodside’s plan to develop a vast offshore gas reserve about 300km off Western Australia’s Kimberley coast. It would extract gas from beneath the seabed near Scott Reef. The project matters because the field is needed to supply Woodside’s North West Shelf gas export plant.

Woodside plans to drill more than 50 wells and connect them to the processing plant with a 1,000km pipeline. The plant sits beside the world heritage-listed Murujuga rock art. Gas would be processed there and exported, while burning it could release carbon dioxide into the atmosphere.

The proposal is being assessed by both state and commonwealth environmental authorities. The WA Environmental Protection Authority initially indicated it would reject the development, but the final decision rests with environment ministers. Woodside has changed parts of its plans to address environmental concerns, including moving wells farther from Sandy Islet.

Scott Reef and Sandy Islet are important because they combine unusual biodiversity with vital wildlife habitat. Scientists say Scott Reef contains more than 1,500 species, including many found nowhere else. The WA Environmental Protection Authority described the reef’s environmental value as exceptional.

Sandy Islet is considered critical to endangered green turtles. About 1,000 turtles breed there each year. Scott Reef is also the only known feeding ground for pygmy blue whales migrating between Timor and southern Australia. Noise, vessel traffic and collisions could interfere with that movement and feeding.

These features make damage potentially difficult to repair. The EPA warned that seabed subsidence could threaten Sandy Islet, while pollution could harm the wider reef. Woodside acknowledged the exceptional value of Scott Reef and Sandy Islet, but said whales used the area opportunistically and considered other southern waters more important.

The development is large in both its industrial footprint and its ecological setting. Woodside wants to drill more than 50 wells in the Browse basin, located about 300km offshore from the Kimberley coast. The gas would then travel to shore through a 1,000km pipeline.

The proposed infrastructure would operate near Scott Reef, an ecosystem supporting more than 1,500 species. Scientists have warned that many of these species are unique to the area. The development also sits near Sandy Islet, where about 1,000 endangered green turtles breed each year, and near a feeding ground for migrating pygmy blue whales.

The article does not provide a precise number of species that would be harmed. Instead, it identifies several groups facing possible impacts: coral reef life, green turtles and pygmy blue whales. The EPA also considered oil spills a broader threat to the reef and its wildlife.

Drilling could harm Scott Reef through several different pathways. A leaking well or oil spill could contaminate the reef and create serious or irreversible damage. The EPA was advised that a leak lasting 13 days might already have irreversible consequences for Scott Reef.

Gas extraction could also cause the seabed to subside. The EPA warned that this could threaten Sandy Islet, an important green turtle breeding site. Noise, vessel traffic and vessel strikes could affect pygmy blue whales as they migrate and feed at Scott Reef. Bright flaring could confuse turtles’ navigation.

The possible damage is not limited to one species or one accident. It could affect coral habitats, endangered turtles and whales at the same time. Woodside has proposed safeguards, but the EPA staff considered the risks serious enough to warn that the project might cause harm that could not be reversed.

The precautionary principle is used when a proposal could cause serious or irreversible environmental harm, even if uncertainty remains about exactly what will happen. It tells decision-makers to act cautiously rather than assume the damage will be minor or manageable.

EPA staff advised that the project threatened endangered turtles, pygmy blue whales and Scott Reef more generally through possible oil spills. They also warned about seabed subsidence, noise, traffic and vessel strikes. A 13-day well leak was considered capable of causing irreversible consequences to the reef.

For that reason, staff advised the EPA board to assume the worst possible outcomes could occur. Their draft letter sharply criticised Woodside’s protections and said topping up Sandy Islet with sand was high-risk, with limited likely success. In February 2024, the EPA told Woodside its preliminary view was to reject development, although environment ministers hold the final decision-making power.

Woodside has proposed equipment and operating changes designed to shorten a well leak or blowout. Its main addition is an explosive-driven shear ram. The device is intended to cut and seal a leaking well quickly, reducing the possible duration of uncontrolled flow.

Woodside said the shear rams could reduce the longest credible duration of a highly unlikely blowout and oil spill to about 12 hours. It also changed the layout by keeping wells at least 20km from Sandy Islet and proposed restricting gas flaring, whose bright light can confuse turtle navigation. If the shear rams failed, Woodside said it would deploy a capping stack within 16 days.

The measures remain disputed. Chevron rejected pyrotechnic shearing for its own wells in 2024, calling it unproven and impossible to test in the field. EPA advice said a 13-day leak could cause irreversible reef consequences, while Greenpeace criticised the plans as relying on unproven technology.

Natural gas is a fossil fuel found in underground deposits and extracted through wells. In this project, Woodside would remove gas from beneath the seabed and send it to a processing and export plant. The gas would then be burned for energy, producing carbon dioxide.

Carbon dioxide builds up in the atmosphere and contributes to climate change. The article estimates that operating the North West Shelf plant until 2070 could lead to about 88 million tonnes of carbon dioxide being released each year after the gas was burned. That climate effect occurs beyond the immediate drilling site.

Environmental protections could reduce local risks, such as oil spills, turtle disruption or whale strikes. They would not prevent emissions created when the gas is ultimately burned. This is why the project raises two separate concerns: possible direct damage to Scott Reef and wildlife, and large ongoing emissions connected with extending gas production and exports.