With nearly half of the states having marijuana legalized in some form, it raises the question of what employers should do regarding workplace drug testing.

Workplace drug testing is up 277% from 1987. Last year, U.S workers peed into one drug testing company’s cups about 9.1 million times and about 350,000 of those cups indicated drug use. Marijuana was primarily the drug of choice, followed by amphetamines and painkillers.

As common as this practice of pre-employment drug testing has become, can you resist hiring or even fire an employee for testing positive for marijuana in states where the drug is legal?

Since marijuana is still considered federally illegal, any workplace that receives federal funding or is subject to federal regulations requiring the testing of safety-sensitive workers must consider marijuana a prohibited substance. A good example of this would be the Department of Transportation.

However, many workplaces do not fall under this category that receive federal funding, and should follow these steps to follow all laws and maintain a safe workplace:

1.) Talk to a lawyer

2.) Review your company’s drug testing policy

3.) Communicate expectations with employees

4.) Train HR on changes

5.) Continue or increase drug testing

One interesting problem that employers are running into is the amount of time that marijuana stays in your system. Although it differs for every individual, THC often has the ability to stay in your system for up to three weeks, while almost all other drugs are out of your system within days.

As long as employers are following the steps above before making changes in their drug testing procedures, they should be able to eliminate future problems and create a safe work atmosphere.