A company is being prosecuted by the Health and Safety Executive (HSE) after three workers died in a tank of farm slurry in July 2004.
Timothy Bartrum, 46, and Graham Morris, 54, both of Thetford, Norfolk, and George Barnes, 28, of Brandon, Suffolk, had been working for Enviro-Waste Ltd.
Mr Bartrum fell into the vat and his colleagues died trying to save him.
The case against the Thetford firm, its director and manager was opened and adjourned by Swaffham magistrates.
Chicken waste
The prosecution by the HSE follows an investigation into their deaths in the tank of chicken waste.
The HSE alleges Enviro-Waste Ltd, of Brunel Way, Thetford, failed to manage the risks of the slurry holding tanks, a breach of the Health and Safety at Work Act 1974.
The company's director, Roger Arthur Clark, and its general manager, Gordon John Betts, are also accused by the HSE of breaching the act by failing to manage the risk to health and safety.
An inquest into the deaths of the three men recorded a verdict of misadventure.
A post-mortem examination showed the men had drowned.
The case has been adjourned for six weeks and will be heard at Norwich Magistrates Court.