Previously, state law barred the assault weapons’ sale to those under 18. The new rules, approved by voters in a ballot initiative in November, come alongside dozens of moves by other states to strengthen gun control regulations in the absence of federal action.

“It is a meaningful step in the right direction,” said Christian Heyne, legislative director at the Coalition to Stop Gun Violence, on Washington’s initiative. “Gun violence on the whole is such a complex problem. We need to have complex solutions, comprehensive solutions. This is a part of that conversation.”

In addition to the age restrictions, Washington’s new rules state that gun dealers must wait 10 days before delivering semi-automatic assault rifles they sell. That is designed, in part, to prevent impulsive action. The rules also require anyone buying a semi-automatic assault rifle to have completed a gun safety training in the past five years. The measure also imposes criminal penalties for unsafe gun storage, and requires more extensive background checks for purchases of the assault weapons.

Most of the new rules take effect in July.

“Every component is extremely important,” said Renee Hopkins, chief executive of the Alliance for Gun Responsibility, the group that sponsored the ballot initiative. “This package really looks to reduce suicide, reduce accidental shootings and also reduce everyday gun violence, interpersonal gun violence, that we see playing out.”

The Nov. 6 ballot initiative passed with more than 59 percent of the vote.

According to the Giffords Law Center to Prevent Gun Violence, state legislatures in 2018 passed nearly 70 gun control measures, more than any other year since the Newtown, Connecticut, massacre in 2012, and more than three times the number passed in 2017.

Opponents of Washington’s ballot initiative said its provisions to safely store guns would make them “unavailable” for self-defense. It also said that banning sale of semi-automatic assault rifles to 18- to 20-year-olds “would leave already vulnerable segments of the population defenseless to attack.” The NRA and the Second Amendment Foundation have filed a lawsuit saying that the age restrictions violate the Constitution.

This article originally appeared in The New York Times.