It will soon be illegal to own or manufacture “ghost guns” within Denver after the Denver City Council passed changes to the city’s weapons code on Monday.

Ghost guns are homemade firearms that don’t have serial numbers or markings, meaning they can’t be tracked to their maker, seller or original owner. They are often made by buying pre-made parts and assembling them at home, or by 3D-printing non-serialized parts.

Currently, Denver’s weapons code allows for ghost guns because the law considers the parts used to assemble firearms to be components, not firearms themselves, said City Attorney Kristin Bronson. That means firearm parts can bypass regulations.

“There is no single solution to preventing gun violence in our communities, but this ordinance is an important step toward keeping these unregistered and untraceable firearms off our streets and out of the hands of those banned from gun ownership,” Bronson said.

Bronson said the existing loophole allows minors and people with criminal records to get guns without background checks. Without a serial number, ghost guns also make it more difficult to solve crimes and get insight into gun trafficking patterns.

The bill makes it illegal for anyone to possess, wear, carry, transport, display, flourish, discharge, manufacture or sell any non-serialized firearm in Denver, including any non-serialized firearm frame or receiver.

The prohibition will go into effect after it is signed by Mayor Michael Hancock, which is expected to happen by Friday.

The bill passed in a 10 to 1 vote, with Councilwoman Candi CdeBaca voting “no” and two council members absent. CdeBaca voted against the bill after supporting a failed amendment that would have pushed back the implementation date for outlawing ghost gun ownership.

Councilman Kevin Flynn proposed the amendment, attempting to delay the prohibition of owning ghost guns to after Sept. 30, allowing owners of ghost guns to decide what to do, including destroying or disposing the weapons.

“This rule would give a legal pathway to serialize these firearms,” Flynn said. “The immediate effectiveness of this prohibition will mainly impact law-abiding owners by not giving them a runway period on which they can make deliberate decisions on how they want to proceed.”

The amendment failed in a 7 to 4 vote, with council members Paul Kashmann and Deborah Ortega joining Flynn and CdeBaca in support.

“We have an extraordinary gun violence problem in our city … we have to act,” Councilwoman Amanda Sawyer said in opposition of the amendment. “It is irresponsible for us, especially on a night where we give a moment of silence to five victims who lost their lives to gun violence last week in our city, for us to amend this at all.”

Members of the City Attorney’s Office also spoke in opposition of the amendment Monday, saying they’re concerned about how many ghost guns will flow into the city by the end of September.

In Denver, 38 ghost guns used to commit crimes have been recovered by police since November 2019, according to the City Attorney’s Office. That means ghost guns account for about 2% of firearms recovered in Denver.

Nationally, at least 23,906 ghost guns were found by law enforcement at crime scenes between 2016 and 2020, including 325 homicides or attempted homicides, according to the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Under the bill, anyone convicted of possessing a ghost gun is subject to forfeiture of the weapon, a fine of up to $999 and up to 300 days in jail.