A New South Wales winery has been fined after a violent explosion left one man dead, and an engineering firm could be made to pay too.

The blast at Draytons Family Winery in January 2008 killed well-known winemaker Trevor Drayton and welder Eddie Orgo.

The coronial inquest into the incident said the explosion was triggered when Mr Orgo was welding a large wine vat.

It is understood that a string of systemic failures led to a high concentration of liquid ethanol vapours which were able to ignite.

William Rikard-Bell, an assistant winemaker, was engulfed in flames and had to douse himself in a nearby dam.

Workcover NSW has prosecuted Draytons Family Wines and Mr Orgo's employer Perfab Engineering for breaches of the Occupational Health and Safety Act.

Draytons has been handed a $210,000 fine, while Perfab is set to be sentenced in December.