Pictured: A faux marijuana Christmas tree sits in the window of Shire Glass, a fine tobacco shop on Main Street in Great Barrington, Mass, Wednesday, Dec. 14, 2016. Dan Meandro, an employee, talks about how his dialogue with customers changes on December 15 with the new laws that allow Massachusetts residents over the age of 21 to possess, use and grow home-grow marijuana. (Gillian Jones, The Berkshire Eagle via AP)

Smoke the reefah: Weed now legal in Massachusetts

BOSTON — Legal-marijuana activists were in a celebratory mood Thursday as a new voter-approved law took effect in Massachusetts, allowing people 21 and over to possess, grow and use limited amounts of recreational pot.

Related: Here’s what you can — and can’t — do with recreational Massachusetts marijuana

It will be at least another year before marijuana can be legally sold by licensed retailers in the state, and some supporters of the measure are wary that Massachusetts officials might seek changes to the law or delay its full implementation over the coming months.

Police warned of a potential spike in people driving under the influence of pot and general confusion about what is allowed under the law.

“Yesterday this would have been a $100 fine,” said Keith Saunders, as he held up a jar containing what he said was slightly less than an ounce of cannabis flower.

Saunders, a board member of the National Organization for the Reform of Marijuana Laws, or NORML, gathered with other activists outside the historic Massachusetts Statehouse to celebrate the law.

“Ultimately, we are moving toward taking the existing marijuana market in Massachusetts and bringing it above board,” he said.

Massachusetts is the first U.S. state on the Eastern seaboard where recreational marijuana is legal, though Maine soon will follow if a recount upholds passage of a ballot measure there. Colorado, Washington, Oregon and Alaska previously legalized recreational pot, and voters in California and Nevada also approved ballot measures last month.

In Massachusetts, adults can possess up to an ounce of pot outside the home, up to 10 ounces inside the home and grow up to a dozen marijuana plants per household.

Having spent nearly three decades crusading for relaxed marijuana rules, Bill Downing admitted to a mix of satisfaction and trepidation.

“I am both celebrating and worrying that the law might not be implemented properly,” said Downing, member liaison for the Massachusetts Cannabis Reform Coalition.

The concerns stem from public statements by Democratic legislative leaders and Republican Gov. Charlie Baker promising a review and possible changes to the law, which passed by more than 240,000 votes out of nearly 3.8 million votes cast.

“It’s legal. I just hope everyone plays by the rules, Baker said Thursday after returning from a trade mission to Israel.

The governor, who strongly opposed legalization, again pledged that the will of the voters will be respected. But he cited “ambiguities” in the law and said legitimate concerns had been raised about public health and safety.

In a memo sent Wednesday to police departments in Massachusetts, Secretary of Public Safety Daniel Bennett said implementation of recreational marijuana “will create a complex web of different rules” that law enforcement must navigate.

“Within certain limits, the new law authorizes some conduct that had previously been prohibited. Beyond those limits, however, possession, cultivation and distribution of marijuana remain illegal under state law,” wrote Bennett.

Marijuana activists dismissed critics who said legalization will lead to an array of social and public safety problems.

“The worst you could do is maybe listen to Pink Floyd for two hours rather than one hour,” a guitar-playing man joked as he serenaded supporters with pro-pot tunes in front of the state Capitol building.