Two workers dead, one critical after toxic gas leak at paper mill

Two men have died following a gas leak at a paper mill in Ettamogah in southern NSW, with another two workers in hospital, one in a critical condition.

More than 100 workers were evacuated from the site. Source: Nine Network

Two men have died and another is fighting for life in hospital after a gas tank leak at a paper mill near the NSW-Victorian border, with authorities describing the incident as "tragic".

The leak occurred at the Norske Skog mill at Ettamogah, north of Albury, on Thursday afternoon, with 150 people evacuated from the site and more than a dozen workers taken to hospital.

Four workers - three Norske Skog staff and a contractor - were on a tank checking valves about 1.30pm after an annual maintenance shutdown.

SafeWork NSW Inspector Scott Kidd says the three men were overcome by fumes, with initial investigations suggesting it could have been hydrogen sulphide.

NSW Ambulance acting inspector Rodney Hannan said within 25 minutes of arriving on the scene, two men were in cardiac arrest and another was unconscious.

A 28-year-old Wodonga man died at Albury Base Hospital on Thursday after sustaining burns and inhaling gas, while a 37-year-old Lavington man died on Friday morning, NSW Police said.

A third worker, also a local, remains in a critical condition while a fourth is seriously ill.

"The injuries and the related fallout from what occurred yesterday are consistent with that gas, but it's yet to be established," Mr Kidd told reporters at the scene on Friday.

He said the gas was already on the site when the incident happened and it wasn't the result of the maintenance work being undertaken.

Hazmat crews, along with a lead inspector, are joining the investigation with hopes they will establish the cause of the "tragic" incident over the weekend, Mr Kidd said.

Investigations are underway. Source: Nine Network

While SafeWork NSW has a "reasonable idea" of what happened, it will wait until all the facts are investigated before releasing it publicly.

"It's going to hit home for a lot of the local people," Mr Kidd said.

"We're calling on unity from the community to bring everyone together at such a tragic time."

He said the overall investigation will be "long and complex" and could take months.

Norske Skog Albury mill general manager Milo Foster told local newspaper, The Border Mail, he and the staff were "devastated" by the incident.

The 12 people taken to hospital for gas inhalation were discharged on Thursday night.

A report will be prepared for the coroner.