Aluminium giant Alcoa has been fined $68,000 over the death of a worker at its Wagerup refinery in Western Australia.
Paul Herbert Fry, 50, fell at least 25 metres to his death through an inspection porthole while cleaning a metal tank in September 2009.
The father of three was employed by Transpacific Industries, which was contracted by Alcoa to carry out the work.
US-headquartered Alcoa pleaded guilty in Perth Magistrates Court to failing to provide and maintain a safe working environment.
The company was sentenced on Friday and must also pay $5000 in costs.
"Alcoa sincerely regrets the circumstances surrounding this tragic accident and once again extends its condolences to Mr Fry's family, friends and workmates," the company said in a statement.
It said the company now required barriers to be installed across inspection portholes where the width of the opening was greater than 30cm.
Department of Mines and Petroleum resources safety executive director Simon Ridge said no fine or penalty could make up for the price paid by Mr Fry and his loved ones.
"The lives of Mr Fry's family and friends have been changed forever because of this tragic but, ultimately, preventable incident," Mr Ridge said.
Transpacific Industries was fined $170,500 in the Federal Court in 2012 over Mr Fry's death.