California has enacted a law that will oblige 3D printer makers to build in features that block firearm printing, but only after ASTM International issues a standard for such technology. It is the second US state to do so after New York. Because no standard exists yet, the duty may never take effect.
What does the California law require?
Governor Gavin Newsom signed a bill that obliges makers of new 3D printers to include firearm-blocking features. The duty applies only after ASTM International, a non-profit body for voluntary standards, publishes or adopts a standard for them. It regulates the sale and transfer of printers, not ownership or use, and printers already sold need no retrofit.
Why might it never take effect?
The state Department of Justice must check for a standard every quarter, starting no later than July 1, 2027, until July 1, 2029. If none exists by then, the checks stop and the rules manufacturers must follow may never be written. Colorado and Washington have similar bills in progress.
What are the technical objections?
Two detection approaches exist: matching files against a database of known gun designs, or using a trained model to judge a design. The first is easy to evade by resizing or splitting a file. The second can wrongly flag legitimate barrels, brackets, levers and tubes. The Electronic Frontier Foundation said in June 2026 that the mandated technology would not work as intended.
What it means
For industrial additive manufacturers the direct effect is small: the law targets consumer printers and depends on a standard that does not yet exist. The practical risk is indirect, as file screening could later spread to software and slicers used in professional workflows, with false positives on ordinary brackets and tubes. Companies in Europe selling into the US should watch the ASTM process, since timelines run to 2029. This follows California's recent lawsuit against filament maker Polymaker, showing the state is approaching the topic from several sides.
Frequently asked questions
Do existing 3D printers need to be changed?
No. The law covers only printers not yet sold, and it regulates sale and transfer, not ownership or use.
When would manufacturers have to comply?
Only after ASTM International publishes or adopts a suitable standard. The state checks for one quarterly between July 1, 2027 and July 1, 2029.
This summary was written with the help of AI from the linked reports, under the editorial responsibility of Svetozar Kolesar.