Maintenance work crews had left for their lunch break on November 11 when the fire broke out at the site’s fuel distribution house.

No one was injured but the blaze caused internal damage to the site’s conveyor, the surrounding chutes and roof.

While there was a person acting as a “fire watch” during the maintenance works, that person did not have to continue monitoring the site during breaks or at the end of the day.

The workers had followed company procedures by hosing down the area before their break but the fire alarm was set off about 10 minutes after they left.

Suppression deluge systems were activated and firefighters were called, with crews taking more than an hour to contain the fire.

WorkSafe found Energy Australia’s procedures should have required the fire watch person to hose down the area and scan it with a thermal imaging camera before leaving.

Energy Australia accepted it had breached the Occupational Health and Safety Act and on Wednesday pleaded guilty in the Victorian County Court.

Company barrister Colin Mandy SC said the Yallourn site had comprehensive fire safety systems at the time of the blaze so the offending should be considered at the lower end.

Energy Australia had also not faced any fire-related offences in the 25 years before this incident nor in the years after, Mandy said.

“This is a company that really does everything it can to operate safely,” he told the court.

“It’s a big company with a complicated, dangerous workplace and it’s doing its level best to maintain levels of safety.”

Mandy said it was open to Judge Peter Rozen to fine the company without conviction given its early guilty plea, prior good history and compliance in recent years.

But prosecutor Peter Matthews SC argued the offending was serious and a conviction with a significant fine was open to the court.

“The penalty for a company of this size needs to be more than small change,” Mr Matthews said.

Judge Rozen will hand down his sentence later in March.