Conservation groups have reached the Supreme Court to challenge key environmental approvals granted to Woodside’s Scarborough Gas project off north-west Western Australia, in order to prevent what they call “staggering amounts of pollution”.

Woodside reached a final investment decision in November for the joint $16 billion LNG development.

Part of the proposal is to pipe gas from the field, approximately 375 kilometres west of the Burrup Peninsula near Karratha, to its existing onshore Pluto LNG plant.

At the heart of the challenge are amendments to the project’s environmental approvals, which the EPA agreed to in August.

The changes were then approved by WA Environment Minister Amber-Jade Sanderson.

Lawyers for the Environmental Defenders Office, acting on behalf of the Conservation Council of WA, told the court in Perth the changes would allow for “significant” extra greenhouse gas emissions, which former EPA chairman Tom Hatton had not properly assessed in deciding on the approvals.

“The inference to be drawn is that the chairman didn’t reach his own decision,” Henry Jackson SC, representing the EDO, told the court on Monday.

Mr Jackson said Dr Hatton approved the changes on the same day he received the application material.

And that a report prepared for him by the environment department recommended simply “noting” the proposed changes and approving them.

“The decision is effectively a ‘cut and paste’ of the Woodside document,” he said.

The original 2019 environmental approvals for the construction of Woodside’s nearby LNG plants only allowed gas from nominated fields to be processed.

But the EPA deleted these restrictions on gas supply sources, using discretion allowed under the EPA Act.

Mr Jackson told the court Dr Hatton was given inadequate time and information to reach that decision.

“Practice doesn’t make perfect, it makes permanent, if (the chairman) is making the same mistake each time,” Mr Jackson said, referring to the hundreds of similar decisions before the EPA chairman at that time.

In documents read to the court, Woodside argued allowing gas from additional fields be processed onshore, would be of “minor consequence” to the overall environmental impact.

The council claims the Scarborough development will result in 1.6 billion tonnes of carbon dioxide-equivalent emissions over its lifetime.

Woodside is expected to begin its first gas shipment from the field in 2026.

In a statement to shareholders at the time of final investment decision, the company said gas processed from the new field “will be one of the lowest carbon intensity sources” of LNG for its north Asian customers.

Lawyers for the Environmental Protection Agency are yet to present their case to Justice Jeremy Allanson. Since the decision in question, Dr Hatton has been been succeeded as EPA chair by Matthew Tonts.

Conservation Council WA executive director Maggie Wood said outside court that her organisation spent several months negotiating with the EPA.

“All we are asking is that the Supreme Court allow for this project to be assessed under the same environmental regulations” as any other project in WA, she said.

The case is scheduled to run until Wednesday, with a decision next year.

-AAP