The Employment Court has taken a sensible tack in giving Air New Zealand the right to randomly drug test staff working in "safety-sensitive areas". No matter how vigorously trade unions argue that such testing would breach expectations of privacy, the safety of the public and, indeed, the employee must be paramount. As the court found, the Health and Safety in Employment Act and general law impose "absolute duties on employers to take all practicable steps to eliminate hazards to employees and others". To suggest that this should not include the random testing of airline staff is to trifle with the greater good; the consequences of drug or alcohol-induced error are simply too calamitous for there not to be an adequate deterrent.

Now, it is up to Air New Zealand, in consultation with the unions, to define "safety-sensitive areas". The court decided it was not its place to decide what the expression means. The task should not be too difficult, however, if the parties build on the court's common sense. Most obviously, the spotlight will fall on pilots, rightly so given the increasing evidence of the effects of drugs and alcohol on their performance.

Lately this has been emphasised by the Australian Transport Safety Bureau report into the Hamilton Island crash of 2002, in which four New Zealanders were among six who died. That report found the pilot had alcohol and cannabis in his system. While the bureau could not definitively link this to the accident, it equally could not discount them as factors. The pilot, it said, could have experienced some degree of spatial disorientation during an attempted right turn he was making just before the crash "as a combined result of the manoeuvre, associated head movements and alcohol-induced balance dysfunction".

As alarming as that finding were the conclusions of a research paper, released simultaneously by the bureau, on the impact of drug and alcohol use. It said scientific evidence indicated that even relatively low doses of alcohol could lead to reduced pilot performance. "Indeed, a significant proportion of fatal general aviation accidents are associated with alcohol use." It also noted that cannabis was now much more potent, and suggested previous research on its health effects might well be conservative.

Unsurprisingly, the bureau's report on the Hamilton Island crash said random drug and alcohol testing should be introduced for aviation staff in "safety-sensitive" areas. A review of this recommendation has been initiated by the Australian Government. It will surely arrive at the same conclusions as this country's Employment Court. But New Zealand can count itself fortunate that public safety has been accorded its rightful priority earlier - and without the catalyst of a tragic accident.

The Employment Court was careful to note that its decision applied only to the circumstances of Air New Zealand and its workers. Few other companies, it said, were of the same scale or in the same specialised field. Nonetheless, the principles implicit in the judgment have ramifications for other industries. Take the forestry and wood-processing sector. Drug abuse has long been cited as a major headache by employers there. The Employment Court's reference to the duties imposed on employers by the Health and Safety in Employment Act and general law would appear to provide grounds for far more than pre-employment testing.

The overriding safety issues in such industries should be accepted by trade unions. Rather than debating privacy concerns, or accusing employers of lacking trust in their staff, they should work with management to introduce suitable drug-testing systems. The degree and nature of the testing will vary from industry to industry, depending on the safety concerns. For none, however, will that concern be more critical than for airline staff.