The Contra Costa County Board of Supervisors on Tuesday passed an ordinance requiring gun owners in unincorporated areas to lock up their guns.

Supervisor Candace Andersen proposed the ordinance, which would require gun owners to use trigger locks or gun safes. On Tuesday, Andersen said she is "a firm believer in the Second Amendment of our Constitution, and nothing that we are doing today takes away someone's right to their arms."

A similar state law is directed only at households with children, and Andersen said she not only wants to also limit access to children, but to adults who are violent, suffering from mental health issues and thieves.

"Just two weeks ago, I was in the community and speaking with some of our deputies, who said there'd just been a burglary in the community, in Alamo, and once again a gun was stolen," Andersen said.

To critics who say dealing with a trigger lock or a safe when they need a gun for home defense takes too much time, Andersen suggested using biometric safes and triggers, rigged for the owner's use.

"(The ordinance) does not prevent someone from carrying their weapon at all times in their homes or having immediate access to it," Andersen said.

The ordinance allows people to report lost or stolen guns within five days to avoid violating the law.

The board asked county counsel to craft the ordinance in July and provided a staff report that said having a loaded or unlocked firearm in the home has been associated with an increased risk of firearm-related injury and death, as well as with the theft of the firearms.

"It is estimated that 200,000-500,000 guns are stolen each year in the United States," reads the report. "Thefts are a source of guns for the commission of other crimes. Recent burglaries in Contra Costa County have included the theft of firearms."

The ordinance will only affect unincorporated areas, though some cities, such as Walnut Creek, already have similar laws. The ordinance, which passed its first reading in a 4-0 vote Tuesday with Supervisor Diane Burgis absent, will come back for an official second reading and implementation on Oct. 3.