Many of the 55 employees at Vangst, a recruiting firm for cannabis companies based in Denver, consume marijuana during a biweekly, virtual all-hands meeting that usually happens around happy-hour time, says Karson Humiston, its 28-year-old founder.

“Some people are drinking an alcoholic beverage, and others are smoking a joint,” she says of their online team hangouts…

“When it was totally illegal, you didn’t have to worry about it in corporate settings too much, but now there are a lot of gray areas,” says Matt Kittay, a corporate attorney at Fox Rothschild in New York who counts cannabis companies among his clients. For instance, some companies producing cannabis products say they have had to rule on employees’ use of them during the workday. Others, including Amazon.com Inc., have stopped drug-testing job applicants and are pushing for nationwide decriminalization.