The shootings of 20 young children and six adult workers last month at a Connecticut elementary school has revived debate not only over gun control, but also over whether the holders of handgun permits should be identified publicly.

The fiercely contested question of confidentiality for handgun permit holders arose last month after the shooting in New York's Lower Hudson Valley published the names of local gun owners. The newspaper, the Journal News, based in Nyack, N.Y., reportedly had to hire armed guards because of the outpouring of anger that greeted publication of its map.

The newspaper acted after the shootings at Sandy Hook Elementary School in Newtown on Dec. 14, which also claimed the lives of the gunman, 20-year-old Adam Lanza, and his mother, spurring new activism for gun control. It was able to get the information through the state's freedom of information, or FOI, laws.

The same information isn't available in Connecticut, because that data is exempt from state FOI law. But after the Newtown massacre, Democratic state Rep. Stephen Dargan introduced a bill to change that. His measure, which has yet to receive its first hearing, would make the names and addresses of about 170,000 handgun permit holders in the state available to the general public, NBC 30 of Hartford reported.

NBCConnecticut: Lawmaker proposes publicizing gun owners' names

"Most things are FOI-able now," Dargan told the Hartford Courant this week. "I don't know why a responsible gun owner is worried about whether a permit for a revolver is FOI-able or not."

If you're wondering whether you can get hold of such information in your state, chances are you can't.

Under a federal law, the FBI conducts an instant background check on prospective gun buyers for federally licensed dealers to make sure the buyers don't have criminal records or are otherwise ineligible. But how the states handle that information once a sale has been approved is all over the map. 

Most states collect the background information from dealers and require a separate state permit to own the weapon. But most of them don't make the information publicly available. 

A survey of the gun registration and permitting in all 50 states by NBC News indicates that 39 of them shield background information, permits and registrations from public inspection, with exceptions for law enforcement and other official agencies. Nine others make the data public or have no laws addressing confidentiality.

In Florida and Illinois, concealed-weapons debate lays bare the politics of gun control

The issue is moot in Vermont, which doesn't require a permit to carry a weapon, and in Nevada, where the picture is unclear.

Nevada state law declares that the identities of applicants for permits are confidential, but in 2010, the state Supreme Court struck down part of the law, ruling that the identity of permit holder should be an open public record once the permit has been issued.

Here's a state-by-state breakdown:

CONFIDENTIAL
Alabama, Alaska, Arizona, Arkansas (.pdf), Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii (.pdf), Idaho, Illinois, Indiana, Kansas, Kentucky (.pdf), Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey (.pdf), New Mexico (.pdf), North Dakota (.pdf), Ohio (limited exceptions for journalists), Oklahoma, Pennsylvania, Rhode Island, South Carolina, South Dakota, Texas, Utah, Virginia, Washington, Wisconsin, Wyoming

GENERALLY OPEN OR NO LAW
California, Iowa, Mississippi (45 days after issuance of permit), Montana, New York, North Carolina, Oregon, Tennessee, West Virginia

After a bloody 2012, some in Congress are seeking to centralize records on gun owners nationwide — Sen. Dianne Feinstein, D-Calif., for example, has proposed legislation that would create a national gun registry, collecting IDs, photos and fingerprints of owners of most legal weapons.

Her proposal says nothing about making the registry public.

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