New Jersey Governor Phil Murphy signed legislation Thursday prohibiting the sale of materials to produce “ghost guns” in the state. The new law criminalizes selling manufactured parts or designs for assembling firearms by non-licensed individuals and effectively makes it illegal for individuals to assemble or possess a 3D printed firearm in New Jersey.

In a public statement, Murphy said that the recent shootings in Pittsburgh and California underscored the importance of passing gun control legislation. “These instances are far too common and we cannot allow any instance of this kind of violence to go unnoticed,” he stated, continuing that “it is through action that we can make definitive changes to end these kinds of deadly mass shootings.”

The law prevents residents of New Jersey from downloading, purchasing or sharing instructions or manufacturing parts for printing a firearm using a 3D printer. These firearms, called “ghost guns” because they bypass existing control laws such as background checks and manufacturer’s serial numbers, have been controversial across the nation, with New Jersey Senator Joe Cryan describing them as “pos[ing] a serious threat” because of their untraceable nature.

The new law is a continuation of his ongoing efforts to tighten gun control laws in New Jersey. In June the governor signed six additional gun control laws, including mandatory background checks for gun sales, limiting magazine capacity for handguns, and stricter permit requirements for handgun owners. The new law was criticized by gun rights advocates while before the legislature as “redundant.” The National Rifle Association stated that it is “already against the law to manufacture a firearm without a New Jersey manufacturer’s license,” and that the new law served no purpose.

The passage of the law comes on the heels of a federal judge banning the distribution of 3D printer instructions for handguns from a Texas-based advocacy group in August.