John Gilmore writes in The Lawyer’s Daily on why employers face a serious challenge in cannabis testing in the workplace—the current science cannot test for present impairment. Cannabis has unique qualities that makes it unlike other drugs or alcohol. It is processed differently by the body, creates inactive by-products, and is retained in body tissue for weeks or longer.

This does not mean employers are without tools to test for cannabis impairment on the job. But their approach needs to be tailored and combine science and physical observations in a way that best fits their business.

In his column John looks at why cannabis impairment is so hard to test for and what methods can be combined by employers. These include urinalysis, oral fluid, blood and physical indications.