DENVER — Pot may be legal, but workers may want to check with their boss first before they grab the pipe or joint during off hours.

Businesses in Washington state, where the drug is legal, and Colorado, where it will be by January, are trying to figure out how to deal with employees who use it on their own time and then fail a drug test.

It is yet another uncertainty that has come with pot legalization as many ask how the laws will affect them.

“There’s just an incredible amount of gray right now” about how marijuana legalization affects employers, said Sandra Hagen Solin of the Northern Colorado Legislative Alliance, a coalition of chambers of commerce.

Police departments are especially worried. Officers take oaths to protect all laws, state and federal. In this case, pot is still prohibited under federal law.