Drug Testing to ensure health & safety in the workplace

10 July 2018

The Health and Safety at Work Act 2015 (Act) significantly altered the health and safety landscape when it came into force in 2016. It brought with it sweeping changes to duties, liabilities and penalties in an effort to greatly reduce workplace deaths and incidents.

Employers need to ensure, as far as reasonably practicable, that their staff, contractors and the general public are kept safe. One area an employer can influence is being vigilant about its staff and contractors being impaired by drugs or alcohol when at work. If an employer is wilfully blind to impairment of its staff and contractors, and an incident occurs, it’s very likely that the employer will be facing prosecution under the Act.

To ensure staff and contractors are not impaired by drugs or alcohol when working, employers need to implement a sound drug and alcohol policy in employment and contractor agreements. This policy should address, among other things:

  1. What will be tested;

  2. What levels of drugs and alcohol constitute a positive test (a commonly recognised standard in New Zealand is the NZ4308:2008);

  3. When testing can occur;

  4. What happens if an employee refuses or obstructs a test;

  5. What to do with a non-negative test;

  6. How that employee will be dealt with following a positive test.

When it comes to testing, the employer needs to first satisfy themselves that they have the contractual right to test in those circumstances. The actual testing should be undertaken by a third party, who can appropriately collect, test and transport the samples.

A sample will usually undergo a screening that will show if it is negative, non-negative or adulterated. A negative test will mean the sample does not contain detectable levels of drugs or alcohol and is usually a good indicator that the test subject is not impaired. A non-negative test is indicative of the sample containing detectable levels of drugs or alcohol, but should not be relied on as a positive result. An employer should always wait until the sample is returned from the lab to see the confirmed levels of drugs or alcohol before proceeding with disciplinary action against an employee.

An adulterated sample means that it has been tampered with, commonly by the use of another person’s urine which is usually cold. It is important to ensure that your policy addresses how to deal with an adulterated sample.

When a sample returns positive, the employee refuses to take the test, or the sample is adulterated, this does not mean the employer can dismiss on the spot. An employer must treat these circumstances as allegations, no matter how strong they view the evidence to be. An allegation must be put to the employee and they must have a reasonable opportunity to explain themselves.

As with all employment dealings, an employer must ensure that they always act in good faith and as a fair and reasonable employer could in the circumstances. The duty of good faith includes, but is certainly not limited to:

  1. Maintaining open and effective lines of communication with employees;

  2. When proposing to make a decision that is likely to adversely affect the employees employment, ensuring that all relevant information is given to that employee and they are given an opportunity to comment before the decision is made;

  3. Ensuring that employees are treated equally and fairly.

With contractors, the duty of good faith does not apply. However, it is advisable to still allow the contractor to explain themselves before terminating the contract as there may be good reason why they failed the test, refused to test, or returned an adulterated sample.

If you have any questions about drug and alcohol testing, or wish to update your Drug and Alcohol policy for your business, please feel free to contact us.


Sam Hood is a Partner in the Court & Disputes/Employment Team at Norris Ward McKinnon. You can contact Sam at [email protected]


Sam Hood