An earthmoving company has been ordered to pay more than $140,000 after an employee was killed by an exploding bitumen emulsion tank last year.

On November 30 last year, an employee of Corboy Earthmovers Limited in Te Awamutu was killed when emulsion was being transferred under pressure from a transport tank - an "emulsion pig" - to a heating tank.

A blockage in the transfer line caused a build-up of pressure in the emulsion pig, causing the rear plate welds to fail, and the rear plate to swing around and hit the victim.

"The issue here, and what industry needs to be very aware of, is that the emulsion pig was not constructed to take pressure and nor was there an over-pressure safety device fitted to it," said WorkSafe Chief Inspector Keith Stewart.

"This company had used pumps to transfer the emulsion up until 2007, and that was a far safer process. When Corboy started using compressed air it did not identify pressure build-up as a risk and it should have used a properly designed and constructed pressure vessel - that would have avoided this tragedy.

"Using pressure to transfer materials between containers has inherent risks which must be identified and managed no matter what the circumstances are, and under no circumstances should containers which are not pressure-rated vessels be used," Stewart said.

Corboy Earthmovers was charged under the Health and Safety in Employment Act with failing to take all practicable steps to ensure the safety of its employee while at work. The charge carries a maximum fine of $250,000.

The company was ordered to pay reparations of $140,319.80 by the Hamilton District Court today. The judge considered an appropriate fine would have been $73,800, but noted the company is in liquidation, so no fine was imposed .