Washington has become 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 Wednesday (NZT Thursday).
''We are making history.''
Washington and Colorado last year legalised the possession of up to an ounce (28.35 grams) of pot 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 70 years.
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 covered everything from the security at and size of licensed marijuana gardens, to how many pot stores could open in cities across the state.
Sales were expected to begin by the middle of next year, with supporters hoping taxed cannabis 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 marijuana industry ruled last month, and sales were expected to start in some cities there at the beginning of 2014.
The two states' rules were largely similar, although Colorado would allow stores to sell recreational and medical marijuana.
Both states would 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 marijuana would undermine the black market, but not so accessible that it would threaten public health or safety.
The board hoped the sale of legal cannabis would capture about one-quarter of the total market in the state, for starters.
Under the rules, the board would issue licenses for up to 334 marijuana stores across the state, with 21 of them in Seattle - a figure some have questioned as too low, considering the city estimated about 200 medical marijuana dispensaries were operating there.
The rules limited the number of licenses that anyone could hold to three - an attempt by the board to stamp out any dreams of marijuana monopolies before they started.
They also prohibited out-of-state investment in pot businesses and required quality-control testing of marijuana by third-party labs.
Marijuana must be tracked from seed to sale, and packages must carry warnings about the potential dangers of pot use.
Colorado's rules required businesses to use a state-run online inventory tracking programme to document the plant's journey from seed to sale.
Marijuana also must be placed in opaque, child-resistant containers before being taken out of a store, and recreational pot stores wouldn't be allowed to advertise to people under 21.
Marijuana shops were set to open in Colorado in January, but only in a handful of cities that have voted to allow them, including Denver.
The federal government announced earlier this year that it would not sue Washington, Colorado or other states over plans to tax and regulate marijuana sales for adults over 21, provided they addressed eight federal law enforcement priorities, including keeping marijuana off the black market and keeping it away from kids
Washington's legal marijuana law included zoning requirements keeping the businesses away from schools, parks and playgrounds.