(NewsNation) — Maryland this week joined a growing list of states as well as Washington, D.C., in restricting the sale and distribution of “ghost guns.”

Ghost guns are usually assembled from kits that lack serial numbers traditionally used to trace firearms.

In the past two years, they’ve been popping up at more and more crime scenes, sparking national debate about how easily accessible they are and prompting a wave of laws to regulate them.

Maryland’s new bill bans the sale of ghost guns starting June 1. Possession becomes illegal on March 1, 2023. The law is going into effect without the signature of Gov. Larry Hogan. He has the option of signing bills, vetoing them, or letting them go into law without his signature.

Hogan, in a statement, called the bill a “positive step” as the state seeks to stem the “tide of violent crime.”

Still, he said, “it does nothing to penalize those who actually pull the trigger on firearms.”

There’s been a federal push to regulate ghost guns, driven by fears that these weapons could easily wind up in the wrong hands. In February, the Justice Department launched the national ghost gun enforcement initiative to prioritize bringing federal charges against individuals who use those weapons.

According to the Giffords Law Center to prevent gun violence, California, Connecticut, Delaware, Hawaii, Nevada, New Jersey, New York, Rhode Island, Virginia, and Washington D.C. have enacted laws to at least partially address undetectable or untraceable guns.