Drugs, alcohol and other substance abuse in the workplace is everyone's responsibility. Work health and safety obligations mean:
employees must not be under the influence of alcohol or drugs or use alcohol or illegal drugs while at work
employers need to manage the work-related risks associated with alcohol and other drugs.
A formal alcohol and drugs policy makes it clear to all workers what behaviour is acceptable. This resource by SafeWork NSW explains how you can develop a workplace drug and alcohol policy for your workplace.