OLYMPIA — Washington would become the first state in the country to ban tobacco for everyone under age 21 under a plan announced Wednesday by Attorney General Bob Ferguson.

Ferguson and lawmakers from the state House and Senate said bills to raise the state’s smoking age from 18 to match the legal ages for consuming alcohol and marijuana were inspired by the effectiveness of smoking bans in several cities nationwide. The first city to do so, Needham, Massachusetts, in 2005, saw a drop of more than 50 percent in its high-school smoking rate by 2012, Ferguson said.

Dozens of cities and counties have followed suit, including New York City, Suffolk County on Long Island, New York, and Hawaii County, which encompasses the state’s Big Island. However, bills to make the smoking age 21 failed in the last two years in New Jersey, Utah and Colorado.

Officials in Washington state cited several studies showing most adult smokers started as teenagers as justification for the change.

“For me, it’s really about helping these kids not have a lifetime of addiction, because that’s what they face,” said Rep. Tina Orwall, D-Des Moines, the lead House sponsor of the bill in that chamber.

The House version of Ferguson’s bill has been referred to the Health Care and Wellness Committee, which is chaired by Rep. Eileen Cody, D-West Seattle, a co-sponsor of the bill. State Sen. Mark Miloscia, R-Federal Way, lead sponsor of an identical Senate bill, said he expects a tough, possibly multi-year fight getting the change through the Capitol.

“This is the start of a conversation,” Miloscia said.

If the change passed, it would cost state government an estimated $20 million a year in tobacco-tax revenues, Ferguson said. Since tobacco’s health effects are largely long-term, any savings to the state’s healthcare system from reducing the number of people who take up smoking would take decades to add up. State government spends a fluctuating amount of money each year to fight tobacco use, particularly among teenagers, from tens of millions of dollars when the national tobacco lawsuits of the 1990s flowed into state coffers to no money at all in 2011 after recession-era shortfalls cut available funds.

Last year, the state spent $3 million on the cause, which is $40 million short of what a Centers for Disease Control and Prevention study recommended for an adequate effort, state Secretary of Health John Wiesman said.

“We obviously don’t have that money,” Wiesman said, calling the proposal a “fiscally conservative approach to that issue.”

An Olympia lobbyist for the Altria Group, a multinational tobacco company, referred calls to a Virginia office that could not be reached Wednesday evening.