King County council members passed legislation Monday that would require secure firearm storage and the King County Sheriff's Office destroy forfeited firearms.

"We simply cannot wait to enact common sense gun safety reforms, and securely storing firearms is the hallmark of responsible ownership," said King County Council Chair Joe McDermott, who co-sponsored the legislation with Councilmember Jeanne Kohl-Welles. "No one policy or piece of legislation can solve the public health crisis of gun violence, but this is an important start.”

The five-piece legislation is part of an initiative to reduce gun violence in King County.

Under the measure, gun owners must safely lock their firearms and ammunition when they are not in use. In 2015, about 150,000 King County adult said they left a firearm unlocked, according to the Washington State Behavioral Risk Factor Surveillance System.

The King County Council passed this measure 6-3; Councilmembers Reagan Dunn, Kathy Lambert, and Pete von Reichbauer were the dissenting votes.

Seattle passed a similar measure earlier this year to increase penalties for failing to safely store a gun.

WATCH: King County Council Chair weighs in safe storage law

The legislation's three other measures require King County to collaborate with youth and young adults to recommend ways to reduce gun violence, require the King County Sheriff's Office to destroy confiscated weapons, and launch a work group to develop gun safety and gun violence prevention programs. The Council passed these measure unanimously.

Part of the bill would also require warning signs be posted outside retail locations, shooting ranges, and places transferring gun ownership. The signs would disclose the "significant" increase in health and life risks from owning a gun and would include contact information for the National Suicide Prevention Lifeline.

They would be available in 10 languages, including English, Spanish, Vietnamese, Russian, Somali, Chinese, Korean, Ukrainian, Amharic and Punjabi, according to King County.

This measure will be voted on by the King County Board of Health.