State of California sues 3D printer filament company Polymaker for promoting ghost guns by marketing to 3D-printed gun community

California is taking another swing at banning 3D-printed “ghost guns,” and this time the target is one of the world’s largest manufacturers of 3D printing filament. Polymaker LLC, headquartered in Shanghai with U.S. operations based in Houston, was named in a civil lawsuit filed October 5, 2026, by San Diego County Counsel on behalf of the People of the State of California. The complaint alleges that Polymaker marketed its filament in such a way as to appeal to gun enthusiasts and thus transform harmless PLA into a regulated “firearm precursor part.”

Under California law, a firearm precursor part is “defined to include any article marketed or sold to the public to become or be used as the frame or receiver of a functional firearm once completed, assembled or converted,” according to the civil complaint filed in San Diego County Superior Court. The County seeks disgorgement of profits, civil penalties and injunctive relief.

The complaint acknowledges that 3D printing filament itself …