OAKLAND, Calif. — As organized labor faces declining membership, one of the country’s most storied unions is looking to a new growth industry: marijuana.

The Teamsters added nearly 40 new members earlier this month by organizing the country’s first group of unionized marijuana growers. Such an arrangement is likely only possible in California, which has the nation’s loosest medical marijuana laws.

But it’s still unclear how the Teamsters will safeguard the rights of members who do work that’s considered a federal crime.

‘I didn’t have this planned out when I became a Teamster 34 years ago, to organize marijuana workers,’ said Lou Marchetti, who acted as a liaison between the growers and Oakland-based Teamsters Local 70. ‘This is a whole new ballgame.’

The new members work as gardeners, trimmers and cloners for Marjyn Investments LLC, an Oakland business that contracts with medical marijuana patients to grow their pot for them.

Their newly negotiated two-year contract provides them with a pension, paid vacation and health insurance. Their current wages of $18 per hour will increase to $25.75 an hour within 15 months, according to the union.

Historically, the Teamsters are no strangers to entanglements with federal law enforcement, from the infiltration of the union by organized […]