Investigation under way after gas pipeline off Victorian coast ruptures | Australia news

The offshore oil and gas regulator is investigating after an undersea gas pipeline ruptured off the Victorian coast, causing a visible “sheen” on the ocean’s surface.

The National Offshore Petroleum Safety and Environmental Management Authority (Nopsema) confirmed it received a notification about a potential spill from ExxonMobil subsidiary Esso on Saturday morning.

It is believed the rupture originates with a pipeline connecting the West Kingfish platform to the Kingfish A platform.

A Nopsema spokesperson said the pipeline was “reported to contain 95% water at the time” but has since been “isolated at both facility ends and is being depressurised”.

“The facility has been offline for four weeks and continues to be so,” they said. “An investigation has been launched and Nopsema is content Esso is currently managing the incident appropriately.”

The regulator did not clarify what remaining material the pipeline was carrying or what may have been dissolved in the water.

“As the investigation is ongoing it would not be appropriate to comment more at this stage,” the spokesperson said.

ExxonMobil Australia has been contacted for comment.

The gas platforms in the area are among the oldest offshore oil and gas operations in the country, with West Kingfish in the early stages of decommissioning.

News of the rupture has prompted calls for more stringent regulations and transparency from the regulator and operators, particularly when it comes to decommissioning old oil and gas infrastructure.

Greens senator Peter Whish-Wilson said he had serious concerns about the rupture, particularly as Esso is applying to set up a carbon, capture and storage (CCS) operation in the area to inject waste CO2 into the Gippsland Basin, beneath the ocean’s surface.

“Nopsema is supposed to have oversight and regulate the environmental management of the offshore fossil fuel industry, but coastal communities are fast losing confidence in the ‘independent’ regulator, which has become more of an enabler than an investigator of offshore oil and gas projects,” he said.

“If Esso cannot manage to decommission rig infrastructure safely I highly doubt it’s capable of carrying out risky carbon capture and storage it has planned for the region.”

Louise Morris, offshore oil and gas campaign manager with the Australian Marine Conservation Society, said the organisation is seeking a full investigation of the incident.

“This rupture of a gas pipeline run by Esso is part of a vast network of dangerous, ageing and rusting offshore gas rigs in our oceans all overdue for shutting down,” Morris said. “It is another example of why the offshore regulator Nopsema needs to be stronger in their regulatory oversight and transparency.”