Medical marijuana and mine sites ā€“ can employees use prescribed marijuana on their days off?

8 November 2023

There is no single answer to this question, however several factors should be considered beyond simply whether the employee passes the workplace drug test or not. 

A recent decision of the Fair Work Commission upheld an employer’s decision to terminate their employee’s contract for use of medical marijuana in breach of their company drug and alcohol policy. This employee, Sheldon Haigh, had passed all drug tests required by his employer Platinum Blasting Services (Platinum) but had not disclosed his return to using prescribed marijuana following an unsuccessful attempt to substitute another medication. 

Haigh was required by the employer’s policy to disclose any medications which may affect his ability to safely perform the requirements of his job. When he returned to taking the prescribed marijuana, he did not advise his employer of this. It came to light that he had returned to using the prescription when there was a near miss incident on site. Drug testing of all involved employees was required, and it was at this time that Haigh disclosed to the tester that he may be positive for marijuana due to his prescription. This was reported to his employer. 

As a result of Haigh’s non-disclosure of medical marijuana use, his employment was terminated. Platinum considered Haigh to have breached the disclosure requirement of their drug and alcohol policy. Haigh believed he did not have to disclosure his prescription as he did not use marijuana on site and ensured that 32 hours elapsed between his last use and commencing work. His view was that therefore, the marijuana could not be considered to impact his ability to perform his job and did not need disclosure. 

The Court found in favour of Platinum, ruling that the wording of the policy as ‘may affect’ required the employee to disclose his use of prescribed marijuana regardless of the precautions he took to ensure it did not in fact affect his work. 

What does this mean for employers?

Employees must disclose the use of medical marijuana even where this occurs only on their time off if their employer has a similarly worded drug and alcohol policy. It is accepted by the Court that use of marijuana may affect a person’s ability to work even where they are not under the influence of the drug while at work.  

[Sheldon Haigh v Platinum Blasting Services Pty Ltd [2023] FWC 2465]

Disclaimer: This summary is a guide only and is not legal advice. For more information, call ECA Legal on (08) 6241 6129 or email