King County’s gun-violence prevention program got a boost this month from billboards and Sound Transit bus ads paid for by the U.S. Department of Justice.

The $30,000 campaign encourages residents to safely store their guns to prevent them from being used to commit crimes, according to a county media release on Thursday.

A 2005 study found that safe storage reduces firearm suicides by 78 percent and unintentional shootings by 85 percent. King County’s LOK-IT-UP campaign is a partnership with Harborview Medical Center, Seattle Children’s, the state Department of Health, and multiple law enforcement agencies and gun retailers working together to promote safe firearm storage.

“A public-health approach to reducing gun violence relies heavily on awareness and education,” said King County Executive Dow Constantine. “Thanks to this investment by the Justice Department, more people in our region are aware of our effective violence-reduction program.”

The Justice Department is helping promote the county’s program as part of a strategy to prevent guns being stolen and used by criminals.

“We need the public’s help to keep their firearms from becoming crime guns,” said U.S. Attorney Annette L. Hayes. “Too often we see criminals using stolen firearms to commit drive-by shootings, domestic assaults, and even murders. Through the Project Safe Neighborhoods program, the U.S. Attorney’s Office is pleased to partner with King County in this media campaign to urge gun owners to practice safe, locked storage of their guns. A locked gun safe can create one more hurdle for those who want to steal, sell and use stolen guns for criminal purposes.”

Just more than half of the adults in Washington state who own firearms — nearly 1 million residents — store their guns unlocked. About 200,000 children in the state live in homes with unrestricted access to guns.

The safe storage campaign is part of Constantine’s broader public-health approach to preventing gun violence, which kills more people in King County than car crashes. The strategy includes helping local hospitals, law enforcement, medical examiners and researchers share data on gun-related injuries and fatalities to better identify the specific risks and needs in the community.

“I encourage all gun owners to take an extra moment to practice safe gun storage,” said Seattle Police Chief Kathleen O’Toole. “A little time can go a long way to prevent gun theft or other potentially tragic misuse.”

“Many guns used by criminals were stolen from law-abiding folks who didn’t lock up their firearms,” said King County Sheriff John Urquhart. “Don’t let that happen to you! Secure your guns, so they don’t get stolen.”

About 70 percent of gun-related deaths in King County are suicides.

“As a community, we can make a difference in eliminating tragedies caused by gun violence,” said Tony Gomez, Public Health – Seattle & King County’s Violence and Injury Prevention Program Manager. “Responsible, safe storage prevents gun access by kids and teens, including those at risk of suicide.”