There is a very strong suspicion that a number of workers are involved in using and trading drugs in our workplace. They have been observed for a number of weeks acting suspiciously on a regular basis in a secluded area during their morning break time, but we have been unable to catch them in the act as definite proof.
We have implemented a drug and alcohol policy and procedure which states that we do casual testing. All employees are inducted in and sign off on the policy.
Would we have reasonable cause to request consent in writing from the workers in question to undergo drug testing, as per our policy and procedure, based on suspicion and not evidence?
This will depend on the wording of your policy. In general, most policies provide for random, casual testing where no requirement of suspicion or evidence is required. One approach would be to select a larger group of workers to be tested which includes the suspected group.