Stena has been fined A$330,000 ($230,000) by an Australian court over the deaths of two rig workers three years ago.
Stena Drilling Australia had entered a guilty plea last week to a charge of breaching its duty to take reasonably practicable steps to implement and maintain systems of work that were safe and without risk to health.
In August 2012 part of a drill on the Stena Clyde semi-submersible rig, which had been drilling in the Bass Strait for Origin Energy, dislodged and killed two workers, Peter Meddens and Barry Denholm.
