Lack of computer program management costs worker his life

The death of an Auckland worker in an engineering plant highlights the need for companies using hi-tech equipment to understand the computer programs underpinning them, says the Department of Labour.

In what is believed to be the first case of its kind in New Zealand, Nu-Con Engineering, of Mairangi Bay, was fined $25,000 on Tuesday in the North Shore District Court over the death of employee Brendon Thickpenny (known to his colleagues as Brendon Stewart) in March 2006. In addition, the company has paid Mr Thickpenny’s wife $79,500 in total, including the continuation of his full wages for two years and a lump sum payment.

Mr Thickpenny was killed after an industrial metal lathe he was operating flew apart sending metal objects - each weighing approximately 2kg - into his legs and abdomen at speeds up to 260kph. This was because the speed set for the rotation of the cutting head he was operating had increased to 3350 revolutions per minute (rpm), far in excess of the 525rpm maximum permitted speed for the particular cutting tool being used.

The resulting Department of Labour investigation showed that Mr Thickpenny had pressed a ‘Reset’ button, but instead of this action returning settings to zero, it returned the machine settings to those of a previously installed program, which were completely wrong for the job being undertaken.

The Court found that Mr Thickpenny’s death was preventable and that he had not been in any way to blame. Nu-Con Engineering admitted its responsibility for the unsafe way the lathe’s computer had been programmed.

The Department of Labour’s Northern Regional manager John Howard says the case highlights the need for computer controlled machinery to be systematically programmed, so that programs are written and installed in a way that allows them to read or take account of each other, rather than operating independently or in isolation from each other.

“Nu-Con did not have appropriate planning and control systems in place,” says Mr Howard. “There was no formal management of the task of writing and maintaining CNC (Computer Numerically Controlled) programmes.

“This was not a situation where a machine designed and built to a proper standard nevertheless malfunctioned or suffered a failure. When the reset button was pressed by Mr Thickpenny the machine behaved according to the way it had been programmed – with successive programs added over time but not in a managed or co-ordinated way.

“Whether Mr Thickpenny pressed the reset button intentionally or inadvertently, he and any other operator of the machine ought to have been protected against the highly dangerous situation that resulted from giving the reset command. It is quite foreseeable that the wrong control might accidentally be touched where many controls are together on a panel before the operator.”

Mr Howard says a practicable step for employers is to ensure that employees understand the safe use of machinery including the way it has been programmed, and to also ensure that machines are properly programmed.

“The consequences in this case have been tragic. The Court heard how Mr Thickpenny’s death has impacted grievously on his wife, his parents, his wider family, friends, co-workers, acquaintances, and not the least on his employer.”