There has been considerable discussion over marijuana use in the workplace in recent years, probably more-so since the Liberal government promised to legalize recreational marijuana use in the last federal election.

The government has now set a date – July 1, 2018. From that time on marijuana will be legal to purchase and possess, but the feds have left it up to the provinces to determine how it will be distributed.

For the employer, it doesn’t change much, legally at any rate. Construction sites can be dangerous places and the employer has a duty to ensure a safe workplace. Smoking pot on the job is no different, in my mind, than drinking alcohol. It just plain isn’t allowed because it puts workers at risk. Impaired is impaired.

Of course, 90 percent of workers go about their duties diligently without any inclination to use mind altering substances at work. But there’s always going to be a few individuals that want to use smoke breaks for things other than cigarettes – that have difficulty separating work from recreation.

The problem is complicated where an employee has a legitimate prescription for so-called medical marijuana. Many of these are not legitimate, so the employer needs to check with the doctor that issued the prescription.

But regardless if it is legitimate, the employer still has a duty to ensure a safe workplace, first and foremost. If the drug – and there are other prescription drugs that also create psychotic effects – is likely to impair the worker’s ability to do their job in a safe manner, they should be excluded if they are in a safety sensitive position, advised occupational health and safety defence lawyer and author Norm Keith of Fasken Martineau in Toronto in a recent presentation to the Ontario General Contractors Association (OGCA).

An employer – or at least co-workers – can usually tell when a person is under the influence. But, other than talking to them and letting them know that you know, it can be difficult to take action.

The courts have ruled that random drug testing is not allowed – and you wouldn’t want to do it anyway because of the demoralizing effect it would have on your good employees. Drug testing can only be done where the employer has reasonable cause and objective evidence of drug abuse, said Keith. There has to have been a significant incident that would lead to the belief that drugs were involved or a “last chance” employment situation, where the employee needs to test drug free to be reinstated.

And marijuana is difficult to test for. According to one expert speaking at a Mechanical Contractors Association of Canada (MCAC) event a few years ago, marijuana stays in the blood stream for a very long time and will show up in a blood test a year later.

None of this will become any easier once marijuana becomes legal. While legalization makes sense in that we don’t want people getting criminal records over relatively inconsequential behavior, it will make it more difficult to maintain a safe work environment.

As usual, the onus will be on the employer and, more than ever, employing the right people is critical – and not so easy to do these days. But that’s a topic for another day!