California Governor Gavin Newsom has signed a bill that will require 3D printer manufacturers to incorporate firearm-blocking technology into new products. The requirement only takes effect after ASTM International publishes an industry standard for such technology, and it applies only to printers sold after that point, leaving existing machines unaffected.
The California Department of Justice is tasked with checking for a standard quarterly from July 2027 until July 2029. If ASTM does not publish or adopt a standard by then, the mandate expires and the rule never goes into force. This makes California the second state to enact such a restriction, following New York, with similar bills pending in Colorado and Washington.
The law's reliance on standards is an attempt to address technical challenges. Current detection methods—matching files against known gun designs or using trained models—are either easily bypassed by modifying files or prone to false positives that could block legitimate parts. The Electronic Frontier Foundation has argued that no mandated technology can work as intended, but the law leaves the specifics to ASTM rather than defining them itself.