Marijuana is big business and big news. Presidential Candidate Hillary Clinton announced that she'd support medical marijuana, Whoopi Goldberg is starting a business with THC laced edibles marketed to women, theoretically for menstrual pain, and the FDA greenlighted double-blind trials for marijuana as a treatment for PTSD.

So, marijuana doesn't look like it's going anywhere soon, and it might have landed in your break room. And in some cases, the company even put it there. Good idea? Bad idea? Flat out, as an HR person, I'd tell you that you don't want any mind altering substance (other than caffeine, and even that has some questionable effects) available on your property. Whether you allow your employees to drink alcohol or smoke marijuana or partake in Whoopi's new PMS treats, you're putting your company at risk.

If an employee gets in her car and crashes into someone else after getting high at work, the lawyers will be looking at your pockets.

But let's take the legal liability off the table just for a second. Do you want your employees operating at less than their best? I spoke with Anne Neu, executive director of the Minnesota House Republican Campaign Committee, about the idea of using marijuana during the workday. Her response:

Terrible idea. I work in an incredibly customer service oriented industry. The majority of my employees are interacting with voters constantly and I need them to be at the top of their game. They are also often directly representing candidates and everything they do reflects on those candidates.

Neu is in politics, where, of course, credibility matters. (Or, heaven help us in this election, should matter.) But what about your business? Does it matter? Of course, it does.

Dr. Kevin Hill is a Harvard University addiction specialist who focuses on new marijuana policy and its impact. What does the change in attitudes towards marijuana mean for your business?

We don't test for alcohol prior to getting a job offer," Dr. Hill points out, "but we do test for marijuana." Employers will have to consider that. Should you be concerned about someone who is using a perfectly legal substance--whether for medical use or recreation? (Given that you live where it's legal.)

While weekend usage may not impact your weekday work, it can, especially in your young employees. Dr. Hill says that people under 25, whose brains are still developing, are far more likely to suffer long-term negative affects from marijuana usage. A 45-year-old smoking on the weekend? Not as damaging.

Unlike alcohol, however, you can't easily test for marijuana usage in the workplace. A quick breathalyzer test allows you to know if someone who is behaving strangely is drunk right now. There's no matching test for marijuana. If your employee is behaving strangely at work and you suspect drug usage, it's difficult to tell the difference between "high right now" and "was high last Friday night." There are blood tests that show the level of THC in the bloodstream, but even those aren't perfect at saying, "this person is high and should not be driving heavy machinery."

For this reason, transportation, and safety-oriented businesses should implement complete drug-free policies. Right now, at least for recreational usage, that's legal even where smoking for fun is legal.

But what about in the actual break room, for people who don't deal with safety issues? Flowhub, a company that makes software for the cannabis industry allows eating and drinking marijuana at work. (They don't allow smoking of any kind.) They say it increases creativity and that they've had zero problems.

However, science says the drug (legal in Flowhub's home state of Colorado) doesn't actually make you more creative--it just makes you think you're more creative. If everyone is partaking, their ability to judge just how creative they are is pretty compromised.

If you want your business to be hip and cool, stay far away from weed at work. There are some good reasons (especially involving hiring) to not care what people do over the weekend, but you're not actually helping your business. You want your people to be at their best at work, and marijuana isn't helping.