All firearm purchases at gun shows on Tacoma city property now require a background checks of buyers.

The Tacoma City Council unanimously approved the change Tuesday, closing the so-called gun-show loophole for events using city space.

The loophole allows people selling guns from their private collections to skip the federal background checks that are required of licensed gun dealers by state and federal law.

“In the face of inaction by state and federal lawmakers our community cannot wait,” said Councilman Ryan Mello.

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The change was sparked by a gun show at the Tacoma Dome last month, the first in 23 years. Of the 152 vendors, 12 were private sellers who could sell guns without a background check.

Wes Knodel, who organized the gun show, wants to schedule five more — one in November and four next year. In all, the Dome could make $275,000 from the shows, says a report from Kim Bedier, director of public-assembly facilities.

Three people at Tuesday’s City Council meeting spoke in favor of the policy change, including Leanne Kennedy, a Tacoma resident who said it doesn’t take much courage to support expanded background checks.

“It takes an extraordinary amount of courage to be the parent of a Newtown first-grader who died,” Kennedy said. It takes courage “to wake up with that kind of hole in their heart.”

No one from the audience spoke against the proposal.

Councilman Marty Campbell spoke of his upbringing in rural Nebraska and called himself a proud gun owner. Speaking from the dais, Campbell said the city “should not facilitate the transfer of weapons to those who would not pass a background check.”

“I believe we all would agree that there are some people who should not have access to guns: felons, those convicted of domestic-violence crimes or those deemed criminally insane,” Campbell said.

Knodel, who did not attend Tuesday’s meeting, said in an interview Monday that the policy change is “invasive and not needed,” but that he would agree to the new terms.

The debate over background checks will continue this summer and fall, as the backers of two statewide ballot measures compete for voters’ support. Initiative 594 would require background checks for all private gun sales, while Initiative 591 would forbid “any government agency” from requiring background checks more stringent than federal law.