Maine will join the 15 states regulating untraceable guns following Gov. Janet Mills' decision to allow such a bill to become law.
The bill requires serial numbers on firearms that can be built at home, including those made with 3D printers, yet have the same lethality as traditional guns.
Regulating so-called ghost guns has become an important issue for gun safety advocates because such weapons are untraceable and evade federal and state firearm laws.
A spokesperson for the governor said Mills believes the bill is an appropriate update to a Maine law that already criminalizes the possession and transportation of a firearm with altered or obscured serial numbers.
The proposal is among more than 60 bills the governor held at the end of this year's legislative session. While the window has passed for Mills to sign those bills into law, they can go into effect without her signature when the Legislature returns in January.
Mills, who is facing a competitive primary in her bid for the U.S. Senate, has a varied record on gun control legislation. She recently opposed a red flag referendum approved by voters, but has also signed an expansion of background checks into law.
