Continuing House Democrats' push to make gun control a top issue of their majority, newly elected Rep. Madeleine Dean (D., Pa.) introduced a bill Thursday aimed at addressing 3D-printed or plastic firearms.

Her legislation seeks to prohibit the possession of firearms that cannot be detected by walk-through metal detectors. It would be an update to the 1988 Undetectable Firearms Act, which requires firearms to contain stainless steel.

The current law “does not adequately address today’s technologies or security risks,” said Dean, who represents Montgomery County. “Today, we face a more pressing issue — firearms made entirely of plastic, or with so much plastic that they fall below the current law’s detection standard.”

The proposal, cosponsored by 15 colleagues including Reps. Chrissy Houlahan of Chester County and Mary Gay Scanlon of Delaware County, would also outlaw “any major component of a firearm that does not generate a gun-shaped image in airport security detection systems," including the slide, cylinder, frame or receiver of any firearm, and the barrel of a rifle or shotgun. It aims to expand the law beyond X-ray machines by ensuring that any standard airport detection device can detect firearms.

The concept of 3D-printed guns sailed into the mainstream over the summer, when a gun rights activist and businessman was allowed by the Trump administration to publish digital files for firearms made with a 3D printer, but was then stopped by the courts. Such a firearm can be made out of plastic with a removable steel part, according to the nonpartisan Congressional Research Service.

Alarmed by the prospect of guns with removable metal parts or all-plastic guns that could go undetected by metal detectors, officials in Pennsylvania, New Jersey, and other states vowed to outlaw the homemade firearms. In November, New Jersey banned them, enacting what its legislators called the strongest such law in the country. Legislation like Dean’s was also introduced in Congress last session.

Also on Thursday, a bill was reintroduced to stimulate the development of gun safety technology. The bill by Rep. Jim Himes (D., Conn.) would provide tax incentives for small businesses to develop technology such as personalized guns or gun accessories that can control who can use the guns using biometric methods or radio wave technology. The legislation is aimed at preventing accidental shootings, such as unintentional gun deaths of children.

The bills reflect the emphasis House Democrats plan to put on gun issues. Speaker Nancy Pelosi introduced a bipartisan background checks bill as one of the first of the new session.

Though Democratic lawmakers have vowed to pass gun control legislation in the House, any measures have a slim chance of passing in the Senate or being signed into law.

Meanwhile, the House Judiciary Committee announced Thursday it would hold a hearing on preventing gun violence next week — the first on the topic in nearly a decade.

“Our new majority is answering the call of the American people,” said Rep. Mike Thompson (D., Calif.), chair of the House Gun Violence Prevention Task Force. “For six years, our task force implored the previous majority to hold hearings and we were denied. This is a new day — we will have a hearing and we will get results.”

The National Rifle Association has called proposals like the background check bill ineffective political plays.