Washington has became the second US state to adopt rules for the recreational sale of marijuana, setting what advocates hope will become a template for the drug's legalisation around the world.
"We feel very proud of what we're doing," said Sharon Foster, chairwoman of the Washington Liquor Control Board, as she and her two colleagues approved the rules on Wednesday.
"We are making history."
Washington and Colorado last year legalised the possession of up to an ounce (28 grams) of cannabis by adults over 21, with voters deciding to set up systems of state-licensed growers, processors and sellers.
The measures put state officials in the difficult position of crafting rules for a fledgling industry barred by federal law for more than seven decades.
The liquor board devised Washington's rules after nearly a year of research, debate and planning, including public hearings that drew hundreds of people around the state.
They cover everything from the security at and size of licensed marijuana gardens, to how many pot stores can open in cities across the state.
Sales are expected to begin by the middle of next year, with supporters hoping taxed pot might bring the state tens or hundreds of millions of dollars, with much of the revenue directed to public health and drug-abuse prevention.
"What the Liquor Control Board has done is build a template for the responsible regulation of marijuana," said Alison Holcomb, the Seattle lawyer who drafted Washington's marijuana initiative.
"This is a template that is going to be reviewed by other states, and already is being reviewed by other countries," including Mexico, Uruguay and Poland.
Colorado approved its pot industry rules last month, and sales are expected to start in some cities there at the beginning of 2014.
The two states' rules are largely similar, although Colorado will allow stores to sell recreational and medical marijuana. Both states will require such measures as seed-to-store tracking, background checks for license applicants, and child-resistant packaging.
Washington liquor board members said they tried to strike a balance between making marijuana accessible enough that legal pot would undermine the black market, but not so accessible that it would threaten public health or safety.
The board hopes the sale of legal pot will capture about one-quarter of the total pot market in the state, for starters.
The federal government announced earlier this year it would not sue Washington, Colorado or other states over plans to tax and regulate marijuana sales for adults over 21, provided they address eight federal law enforcement priorities, including keeping marijuana off the black market and keeping it away from kids