A recent ruling by Fair Work Australia has found that making employees submit to urine tests for drug use is "unjust and unreasonable" as the tests can detect drug usage from the weekend. This may have no bearing on an employee's ability to do their job safely.

State-owned Endeavour Energy was seeking to introduce urine tests for drug use as part of their duty to provide a safe workplace to all employees. Safety is paramount when working with electricity and there is no margin for error. Even the smallest mistake can be fatal or cause severe and permanent injury.

Union members argued that employees could fail a urine test even if they are not still under the influence of a particular substance. Urine tests can show a positive result for cannabis, for example, even if it has been a few days since an individual smoked their last joint. THC, or Delta-9-Tetrahydrocannabinol, the psychoactive compound in cannabis, can remain in the body for up to 90 days. Cannabis takes longer to leave the body than most other drugs because it is fat soluble, rather than water soluble and is stored in an individual's fat cells. Just how long depends on a number of factors including frequency of use, an individual's metabolism, level of exercise and diet. While cannabis remains in the body during this time, it no longer has the same effects or impairments as when it was initially taken.

Fair Work Australia ruled in favour of the Union members who argued that oral swab tests should be used instead of urine tests. Oral swabs will only detect THC a few hours after consumption when the user is still impaired and when their ability to do their job will be most affected.

Drug testing of employees is becoming increasingly common in New Zealand in certain job sectors such as aviation and mining where the ability of employees to carry out their work safely is paramount. The Health and Safety in Employment Act 1992 requires employers to take all practicable steps to eliminate workplace hazards. The introduction of testing for drugs and alcohol in the workplace is one way in which employers can seek to meet these obligations.

In 2004, the Employment Court sanctioned drug and alcohol testing in the workplace in NZ. In relation to Air NZ's policies in this area, the Court held that it was lawful for employees in "safety-sensitive" roles to be randomly tested and for all employees to be subjected to post incident and reasonable cause testing. Reasonable cause testing is where the employer has good grounds to suspect that an employee's behaviour is an actual or potential cause or source of harm to others as a result of being affected by alcohol and/or drugs.

Workplace drug testing policies in New Zealand must take into account the Privacy Act 1993, the New Zealand Bill of Rights Act 1990, and the Human Rights Act 1993. Any testing should be done with the informed consent of the employees concerned. While employees cannot be forced to provide a sample or to consent to have a sample tested, it is usual for a company's or organisation's policy to state the consequences and disciplinary process following a refusal.

Unlike Australia, it appears that urine testing is still the preferred testing method for cannabis use in the workplace in New Zealand. In 2007, the Employment Court held that oral swab testing was not sensitive enough to reliably and accurately detect cannabis. Oral swab testing was criticised for returning more false positives or false negative results than urine testing. Oral swabs also do not reliably detect the presence of benzodiazepines. The Court stated that the fact that a test may pick up earlier cannabis use will have to be the subject of discussion between employee and employer so that the degree of significance of impairment can be assessed.

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