Two companies are facing charges in Western Australia over the drowning of a plumber on a Perth construction site.
Ryan Duffus, 26, died in October 2018 when the trench he was working in at a Mosman Park site filled with water and sand after a water main burst.
His coworkers tried frantically to save him, attempting to pull him out and throwing him pieces of pipe to use as a snorkel.
WorkSafe WA on Thursday said it had commenced prosecution against Mr Duffus' employer and another company.
Ryan and Melissa Pty Ltd - trading as Vivian Plumbing and Civil - has been charged with causing the death of an employee in circumstances of gross negligence by failing to provide and maintain a safe work environment.
Badge Constructions (WA) Pty Ltd, which hired Vivian Plumbing as a contractor, has been charged with failing to provide and maintain a safe work environment and, by that failure, causing the death of a person.
The companies face maximum fines of $2.7 million and $2 million respectively.
WorkSafe WA Commissioner Darren Kavanagh said the case was the first to be launched under the increased penalty regime introduced in 2018.
"Vivian Plumbing and Civil and Badge Constructions face significant penalties, as should be the case when a young worker has tragically lost his life," Mr Kavanagh said.
"Vivian Plumbing has been charged with gross negligence in relation to this incident, the most serious offence possible under the Occupational Safety and Health Act."
The companies will face Perth Magistrates Court on October 16.
WA's parliament is yet to pass industrial manslaughter legislation, introduced late last year, which would enforce a maximum penalty of 20 years' imprisonment for workplace deaths.