A second man has died after a gas tank explosion at a paper mill near the NSW-Victorian border with a third worker continuing to fight for life in hospital.
The explosion 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.
One man died at Albury Base Hospital on Thursday after sustaining burns and inhaling gas, while another worker died overnight, police confirmed with AAP on Friday.
A third worker remains in a critical condition.
Four workers - three Norske Skog staff and a contractor - were on a tank checking valves about 1.30pm after an annual maintenance shutdown.
"They were apparently all overcome, to varying degrees, by a gas, we think it's hydrogen sulphide," Norske Skog Albury mill general manager Milo Foster told the local newspaper, The Border Mail.
Mr Foster said on Thursday night he and staff were "devastated" by the death.
Another 12 people were taken to hospital for gas inhalation but were expected to be discharged on Thursday night.
The mill is expected to release a statement on the incident on Friday morning.
SafeWork NSW said it was investigating the incident.